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PNAS Peer Review Record
Spectral Framework

This page provides the complete review record for three Spectral Framework research manuscripts submitted to PNAS as a coordinated package, together with the cover letter, editorial decisions, referee reports, point-by-point author responses, and the empirical and mathematical evidence relevant to the manuscripts’ evaluation. Its purpose is to provide scientific transparency by making both the review process and the underlying evidence directly inspectable, and to determine whether the manuscripts were evaluated on their actual questions, methods, results, predictions, and evidentiary support. The record distinguishes technical criticisms from claim or method mischaracterization, question substitution, and epistemological assumptions.

A revealing example from the review record

Faced with falsifiable quantitative prospective predictions in Paper 2, the sole reviewer states:

“There are predictions for elements where no calculation nor experiment are available. If they are measured and found to agree with the author's formula, the author will argue that it proves the predictive power. Presumably, if a measurement is found not to agree with the author's recursive fitted formula, a new formula will be fitted with perhaps one or more additional parameters in the fit”.

In addition to speculating about the author’s future conduct, and labeling the work as curve-fitting without identifying a single failure, the reviewer conflates two different situations: a theoretical relation that may be revised by introducing additional terms, and an empirical relation (this work) already fixed by existing measurements, with no free parameters. More concerning, the reviewer’s comment undermines the logic of falsifiability by pre-emptively discrediting both possible outcomes of a prospective quantitative test. The same reviewer further asserts that the paper “contains little physics,” while simultaneously claiming that “physics (theory) is contained” in the empirical measurements themselves.

These comments are particularly revealing of the epistemic framing in which the papers were reviewed. Empirical evidence is either ignored or dismissed by a theory-first narrative of curve fitting and “theory hidden in the measurements,” even when no theoretical input is used. This mode of reasoning, recurrent throughout the reviews, insulates the preferred theoretical interpretation from empirical challenge and renders any proposed alternative dismissible by construction, irrespective of the evidence.

SUBMISSION RECORD

What was submitted, and how it was reviewed

The PNAS cover letter described a coordinated package of three research articles plus an accompanying Perspective and explicitly requested coordinated editorial handling and review because the manuscripts were empirically and conceptually interconnected. This page focuses on the three research manuscripts and the decisions and reports they received.

PNAS 2026-20598

Universal Spectral Scaling and Hierarchical Organization in Atomic Spectra

Editorial decline · no external review
PNAS 2026-20616

A scale-invariant spectral spacing law predicts atomic K-edge frequencies…

1 referee · rejected
PNAS 2026-20623

Atomic Periodicity as Spectral Structure

2 referees · referees disagreed, one rejected
Central editorial issue. The available external record shows that the foundational manuscript received no external technical review, the K-edge manuscript received one referee report, and the periodicity manuscript received two referee reports. The reports do not demonstrate a coordinated technical evaluation of the package as a connected body of evidence. Instead, the manuscripts appear to have been evaluated largely in isolation, with no indication that the referees were given the companion papers or were aware of key results and arguments contained elsewhere in the coordinated submission. This is consequential because several criticisms concern questions, assumptions, or missing context that are directly addressed by the companion manuscripts. Evaluating the papers separately therefore risks treating an intentional division of a connected scientific framework as incompleteness within an individual manuscript. A detailed response to the editors is provided here.
Central referee issue. The central concern is that epistemological assumptions largely substituted for a technical and quantitative assessment of the evidence. The review repeatedly demanded a mechanistic theoretical explanation, although the work demonstrates that the reported organization, prediction, and explanation can be achieved without that theoretical apparatus. It also invoked the unfalsifiable claim that theory is implicitly contained in the measurements, or dismissed the work as curve fitting without identifying a specific methodological or mathematical failure. The review did not engage with the central question raised by the work: how can a simple two-coordinate system in frequency space recover the atomic and periodic organization, predict spectral properties with substantial compression and precision, and generate explicit, falsifiable predictions, achievements that normally require complex theoretical machinery and extensive computation? A substantive critique should identify a specific flaw in the construction, validation, statistical analysis, or inference and explain its consequences for the conclusions. A point-by-point response to the referees is provided here.
SUBMISSION RECORD

PNAS cover letterPDFDownload PDF

Submission: Universal Spectral Scaling and Hierarchical Organization in Atomic Spectra

Editorial Board
Proceedings of the National Academy of Sciences

Subject: Concurrent Submission of a Four-Manuscript Package on Spectral Organization in Atomic Systems

Dear Members of the Editorial Board,

We respectfully submit a coordinated four-manuscript package consisting of three research articles and one accompanying Perspective.

Across three independent studies, scaling laws, periodic organization, physical-property classification, and heavy-element predictions all emerge from relationships among only two experimentally measured spectral parameters. The same two-variable description organizes nearly one hundred elements, ionization sequences, hydrogen spectral families, conductivity classes, magnetic classes, and the heavy-element K-edge series. Remarkably, these structures become visible when atomic systems are organized by a directly measured spectral boundary rather than by atomic number.

The first research article demonstrates that atomic spectra from nearly one hundred elements, ionization sequences, and hydrogen spectral families exhibit common scaling relations governed by a single spectral boundary coordinate nmax. The second shows that periods, chemical groups, major periodic transitions, conductivity classes, magnetic behavior, and other detailed features of periodic organization emerge directly from relationships among two measured spectral observables. The third identifies an empirical scale-invariant spacing law that constrains neighboring K-edge frequencies across the heavy-element regime and provides accurate predictions into the superheavy domain and beyond without theoretical input, achieving sub-percent agreement with independent relativistic reference values.

While each study is independently testable, all three converge on the same organizing coordinate and reveal complementary aspects of a common empirical pattern. The central result is therefore not a single scaling law, classification scheme, or predictive equation, but the repeated emergence of organization, classification, explanation and prediction from the same small set of experimentally measured spectral variables.

We recognize that the inclusion of a Perspective alongside research articles is unusual. The Perspective does not introduce new empirical results. Rather, it synthesizes the implications of the three studies and anticipates a question that may be raised during evaluations of individual components of this work: whether these findings represent isolated phenomenological observations or manifestations of a broader and deeper organizing principle. The Perspective also examines the historical role of atomic number as the dominant organizing coordinate of atomic science and asks whether the newly identified spectral boundary organization warrants reconsideration of that role.

The package consists of:

  1. Perspective: It is Time to Talk About Z
  2. Universal Spectral Scaling and Hierarchical Organization in Atomic Spectra
  3. Atomic Periodicity as Spectral Structure
  4. A Scale-Invariant Spectral Spacing Law Predicts Atomic K-Edge Frequencies of Heavy and Superheavy Elements (Z=100-150) Without Relativistic Input

Because the manuscripts are empirically and conceptually interconnected, we respectfully request coordinated editorial handling and review. We believe the central question raised by this work, whether large portions of atomic organization become visible when atomic systems are represented through spectrally derived coordinates rather than atomic number, is well aligned with the multidisciplinary mission of PNAS.

Thank you for your consideration.

Sincerely,

Abdennour Abbas
Email: aabbas@umn.edu

AUTHOR COMMUNICATION

Proposed changes to package structure and reviewPDFDownload PDF

I. Package Structure

I would welcome the opportunity to revise the package for a coordinated technical review using the latest preprint versions of all manuscripts, which incorporate revisions and new findings developed since the original submission.

I also propose adding the recently completed paper “Empirical Evidence that Dirac–Fock Relativistic and Quantum Corrections are Z-indexing Artifacts” [link] to the coordinated package for four reasons:

• It directly answers a referee criticism of Paper 2. The referee wrote that the manuscript “makes no effort to link his recursive formula for calculating K-edge energies to any meaning about the relativistic Dirac theory with additional corrections.” The new paper answers that question directly by showing that the Spectral Framework predicts not only the empirical spectral values, but also the values obtained by relativistic and quantum calculations without using those theories, and explains where and why the empirical and theoretical predictions diverge. The paper is accompanied by an interactive predictive engine [link], to facilitate visualization, understanding and verification.

• It directly continues Paper 2. Paper 2 identifies the empirical K-edge spacing law, uses it to predict heavy- and superheavy-element K-edge energies, and reveals a systematic divergence from Dirac-Fock values at high Z. The new paper explains that divergence.

• It provides the most direct evidence for the central organizing claim of the package. The package argues that atomic number Z is an ordinal index, whereas νmax is the internal metric coordinate of the spectral system. The new paper tests that distinction directly and shows that the growing mismatch between the two coordinates accounts for the systematic divergence between empirical and theoretical predictions.

• It should make the package easier to understand. Paper 1 was declined without external review because the framework was considered “very confusing and not understandable.” The new paper connects the empirical Spectral Framework directly to the familiar Dirac-Fock description, providing a conceptual bridge to conventional atomic theory.

The resulting sequence is: Paper 1 establishes the empirical spectral framework; Paper 2 establishes prediction and reveals the high-Z divergence; the new paper explains that divergence; and Paper 3 demonstrates the broader generality of the framework across periodic and chemical organization.

II. Proposed Criteria for Coordinated Technical Assessment

Because the previous reviews repeatedly relied on broad labels, mischaracterizations of claims and methods, and theoretical or epistemological assumptions rather than identifying specific technical failures, I suggest that any coordinated reassessment be organized around explicit, testable criteria:

1- Reproducibility and technical validity: The label “curve fitting” should not substitute for identifying a specific failure in the data, methods, statistical analysis, mathematical reasoning, validation, reproducibility, or predictive performance.

2- Predictive validity and falsifiability: Assess whether out-of-sample and prospective predictions follow from the stated empirical inputs and fixed relations alone, without theoretical information, element-specific adjustment, or post hoc refitting, and whether the framework makes explicit predictions that can be contradicted by future measurements or calculations. Claims that the measurements already “contain” the relevant theory should not substitute for identifying where precisely theoretical information enters the mathematical construction.

3- Coordinate comparison: Assess whether organizing the same atomic data by the spectral coordinate νmax reveals reproducible scaling relations, spectral lineage, periodic structure, or other organization that is obscured, distorted, or not recovered when the same data are indexed by Z. Any reviewer claim that Z is equivalent or superior should be supported by direct quantitative comparison with the reported evidence and results, rather than by theoretical expectation or general assertion.

4- Compression: Assess whether the framework achieves substantial reduction of descriptive complexity, recovering multiple atomic, spectral, periodic, and predictive relationships from a small set of measured variables and fixed empirical relations, as compared to existing theoretical models, and whether that compression is maintained without loss of predictive accuracy or introduction of hidden parameters.

5- Generality and explanatory discrimination: Assess whether the same empirical spectral framework recovers independent forms of organization across atomic spectra, heavy-element prediction, periodic structure, and physical and chemical properties, and whether competing explanations can be distinguished by specific measurable evidence rather than assumed theoretical priority.

6- Evidentiary completeness: Claims that data, statistical analysis, validation, or supporting evidence are missing should identify the specific absent item and be checked against both the main text and Supplementary Information.

7- Novelty: Any claim of lack of novelty should identify the specific result alleged to be already known, cite prior literature demonstrating that same result, and compare it directly with the corresponding claim and results of the manuscript. General references to the broader topic should not substitute for that comparison.

8- Independent convergence and cross-paper consistency: Assess whether independently derived results across the four studies converge on the same spectral coordinates, regime boundaries, scaling structure, and predictions without those relationships being imposed across analyses.

PNAS 2026-20598 · PAPER 1

Universal Spectral Scaling and Hierarchical Organization in Atomic Spectra

Foundational manuscript for the shared spectral coordinate and hierarchical organization used by the companion studies.
No external technical review
Editorial decision

Editorial decision

“The editor found this paper very confusing and not understandable.”

The decision letter also states that the Editorial Board initially had difficulty securing an available editor with appropriate expertise and explicitly notes that the editorial decline did not constitute an evaluation of the technical quality of the work.

PNAS decision email · Paper 1
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Original PNAS decision email screenshot.

Response to editor

Response to Editorial Comment · Paper 1PDFDownload response PDF

What Paper 1 Does

Historically, empirical spectroscopic laws such as the Rydberg and Moseley relations revealed precise regularities in atomic spectra, but the available data were not sufficient to determine whether multiple such relations formed parts of a larger closed empirical structure, and theoretical explanations were invoked to fill that gap and those isolated laws were often characterized as curve fitting or correlations. Modern atomic datasets make it possible to test several observables and scaling relations simultaneously across the periodic system. This changes the scope of empirical analysis beyond curve fitting: instead of identifying isolated spectral laws, one can now uncover new relations in the frequency domain (measurement space) and ask whether these relations form a closed, explanatory, and predictive structure without requiring theoretical assumptions or a prior model of the atom as input. This is the overarching question directing the present body of work and the central conclusion of Paper 1: the measured spectral variables do not merely exhibit isolated correlations; they form a closed empirical spectral structure capable of organizing, generalizing, predicting, and explaining the observed data using only two measured frequencies. The subsequent papers then test specific consequences of that structure, including the recovery of periodic organization and quantitative prediction in the heavy-element regime.

It is this combination of empirical closure, extreme dimensional compression, quantitative prediction, and cross-system generality that we had hoped would receive direct scientific evaluation in terms of novelty and reproducibility.

What Does Paper 1 Achieve and How

The manuscript removed quantum-mechanical annotations from the spectral dataset and asked whether organizational principles could emerge directly from frequencies. It compared νmax-based and Z-based representations and tested whether the resulting coordinate constrained spectral lineage, bandwidth, fine structure, K-edge spacing, isotope multiplicity, and hydrogen-series organization.

The submitted analysis reported simple power law and linear global spectral organization under νmax, continuous inter-element mode trajectories and bifurcations, a fractional K-edge spacing law, globally constrained fine-structure scaling, and persistence of boundary-controlled organization within hydrogen where Z is fixed.

Why Is It Confusing

The difficulty in understanding the manuscript may partly arise from two factors.

Editorial Context: The manuscript appears to have been evaluated independently of the hierarchy of evidence across the submitted body of work. The papers are not parallel applications of unrelated ideas; they form a sequential empirical structure as explained above. If these results are independently reproduced, their significance is potentially very large because they would show that a substantial amount of atomic organization normally approached through high-dimensional theoretical machinery possesses a remarkably compressed empirical structure directly accessible in measurement space. That would remain scientifically important even if conventional quantum theory ultimately explains every observed relation. The existence of this degree of empirical predictive compression itself requires explanation.

Conceptual Context: The difficulty may also be conceptual. The paper asks the reader to temporarily set aside the conventional ontology of atomic physics and examine spectra as an empirical geometric and scaling system. 

Conventional chain
Theoretical model → Hamiltonian → states/orbitals → transitions → spectra
↔
Empirical chain tested here
Measurements → spectral coordinates → scaling relations & invariants → organization, prediction & explanation

Theoretical interpretation is deliberately placed downstream of first establishing whether the empirical structure exists in the measurements. That is conceptually unfamiliar, but it is not the same as being incoherent or unintelligible. Comments on the companion papers reveal a similar difficulty: the empirical results are often evaluated through the lens of conventional theoretical models, even though the central question is whether the measured structure is empirically sufficient on its own. The work cannot be adequately evaluated if theory is implicitly treated as the ground truth for explanation and empirical structure as merely curve fitting, even if it organizes, predicts, and provides a structural explanation of the data.

PNAS 2026-20616 · PAPER 2

K-edge spectral spacing law

A scale-invariant spectral spacing law predicts atomic K-edge frequencies of heavy and superheavy elements (Z = 100–150) without relativistic input.
1 referee · rejected
Editorial decision

Editorial decision

The decision states that the manuscript was assigned to an editor and one expert reviewer and was rejected because the issues raised by that reviewer were judged sufficient to merit rejection. The editor added: “This manuscript is not suitable for PNAS.”

The following response therefore addresses the single technical report point by point.

PNAS decision email · Paper 2
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Original PNAS decision email screenshot.

Response to editor

Response to Editorial Comment · Paper 2PDFDownload response PDF

The Editorial Comment states only that “This manuscript is not suitable for PNAS,” while the decision letter makes clear that the rejection was based on concerns raised by a single referee. I therefore respectfully ask the Editor to examine the detailed response below, because several central objections do not test the empirical claims actually made in the manuscript, several comments contain a mischaracterization of the methods and claims, and the core criticism rely on epistemological judgement rather than identifying technical defects in the work.

The most consequential problem is that the referee does not evaluate the manuscript on the empirical grounds on which it was designed. This paper is part of a coordinated empirical framework whose deliberate methodological premise is to begin with measured spectral quantities alone, without introducing theoretical atomic entities, model-dependent variables, or relativistic corrections as inputs, and to ask what structure and predictive relationships can be recovered directly in measurement space. The foundational manuscript (2026-20598) establishes that empirical spectral structure; the present manuscript tests one of its strongest quantitative consequences by asking whether the experimentally observed heavy-element spectral-spacing law can predict K-edge frequencies into the superheavy regime.

The referee instead repeatedly treats the absence of a derivation from Dirac theory, many-electron calculations, or QED corrections as evidence that the work contains “little physics content”, while simultaneously claiming that “physics (theory) is contained” in the empirical measurements themselves. Beside the contradictory statements, this reverses the logic of the investigation. The manuscript does not dispute that these theories can calculate K-edge energies, nor does it claim to derive or replace them. The empirical question is precisely why a remarkably simple structure involving only two measured spectral quantities can reproduce and predict, at sub-percent accuracy, behavior ordinarily approached through substantially more complex theoretical machinery. If that empirical structure is real, its existence and predictive compression require explanation regardless of whether established theory ultimately accounts for it.

This conceptual misreading also leads to one of the report’s central objections: that beginning the prediction from an experimentally measured K-edge constitutes “relativistic input” because the measurement is presumed to contain relativistic effects. This reasoning is circular and unfalsifiable. If relativity is assumed to be embedded in the measurement, then any empirical model using that measurement can automatically be described as containing relativistic input, regardless of whether relativistic theory enters the model at all. No empirical result could then demonstrate independence from the theoretical machinery, because that independence has been excluded by definition. This is a direct consequence of granting theoretical interpretation epistemic priority over the measurement itself: the theoretical explanation is assumed to be intrinsic to the observation before the empirical alternative is tested. The argument therefore assumes the very point the manuscript is testing: whether the observed structure and predictions can be recovered from measurements alone, without relativistic theory as an input.

More importantly, the referee does not demonstrate that the central empirical result fails. The report does not show that the spacing law fails validation, that its heavy- and superheavy-element predictions lose their stated accuracy, or that the frozen recurrence lacks predictive content beyond its construction data. Nor does it address the central empirical fact that a simple relation between two measured spectral quantities reproduces, at sub-percent accuracy, behavior ordinarily obtained through complex many-electron relativistic calculations and supercomputer-scale computation. Dismissing the result as “curve fitting” without single evidence of failure does not answer these questions.

Instead, the recommendation for rejection rests substantially on the view that an empirical relation has insufficient physical significance unless it is interpreted through the existing theoretical framework. The accompanying point-by-point rebuttal documents this issue, together with the report’s additional conceptual, mathematical, and methodological problems, with the corresponding evidence and calculations.

Central editorial question. Did the review test the manuscript’s empirical proposition, or did it replace that proposition with the additional requirement that the result first be derived from or interpreted through Dirac/QED theory? The point-by-point record below separates those two questions and identifies where the report changes the claim, method, or evidentiary standard being evaluated.

This is particularly consequential because the present manuscript was submitted as part of a coordinated body of work. The foundational paper (2026-20598) establishes the empirical spectral structure from measured atomic spectra; the periodicity paper (2026-20623) tests whether conventional atomic organization emerges from that structure; and this paper tests whether the same framework has genuine quantitative predictive power in the heavy and superheavy regime. Evaluating the present paper simply as an isolated curve-fitting exercise therefore misses both its methodological basis and its role as an independent predictive and organizational framework of the broader empirical structure.

I therefore respectfully invite the Editor to examine the detailed rebuttal and point-by-point response before allowing the recommendation of a single referee to stand as the final technical assessment of this manuscript. The issue raised by the rebuttal is not merely a disagreement over interpretation. It is whether the manuscript was evaluated according to the empirical question it actually asks, whether the referee’s central objections are technically sound or rest on epistemological assumptions, and whether the reported quantitative evidence was ever subjected to a direct test. Given the significance of those questions, I believe the basis for the rejection warrants direct editorial reconsideration.

Reviewer 1 · comment and rebuttal

Reviewer 1PDFDownload point-by-point PDF

Review assessment Summary

The reviewer recommends rejection without identifying a single failure in reproducibility, methodology, statistical analysis, predictive accuracy, or evidentiary support for the claims. The reviewer does not even engage with the central question of the work: how can a major atomic spectral property, the K edge, be predicted with a simple linear equation using only two measured spectral quantities, when the standard theoretical account requires extensive computation and multibody calculations? The rejection rests predominantly on epistemological judgments about what counts as physics, what scientific explanation is acceptable, whether an empirical structure may be dismissed as “curve fitting” because it is derived directly from measurements, or whether empirical results must be interpreted through a preferred theoretical ontology before they warrant attention. Such judgments should not substitute for an objective technical and quantitative evaluation of the claims. The point-by-point response below demonstrates the basis for this assessment

“This article is a data science study based on pattern recognition and curve fitting…. There is of course a precedent for finding fitting functions that appear to describe observed patterns relating to physical phenomena”

The characterization of the work as “pattern recognition and curve fitting” does not address the central empirical claim. The manuscript does not merely fit a function to existing observations; it identifies a fixed relation between measured spectral quantities and uses that relation to generate quantitative predictions beyond the data used to establish it.

Once the empirical spacing law and its coefficients are fixed, the predictions are fixed. There is no element-specific adjustment, residual correction, target-specific scale factor, or free parameter available to force agreement. The predictions therefore place the law at genuine empirical risk: agreement constitutes prospective predictive success, whereas disagreement outside the stated uncertainty falsifies or delimits the law.

The distinction is also broader than extrapolation from a single fitted relation. Across the coordinated package, the same low-dimensional spectral organization is tested across independent observables and phenomena, including spectral structure, periodic organization, atomic and chemical properties, and heavy- and superheavy-element prediction. The scientific question is therefore whether a common empirical structure survives independent tests and generates information beyond the data from which each individual relation was obtained.

Calling this “curve fitting” does not demonstrate that the structure is accidental, that the validation fails, that the predictions are quantitatively unsuccessful, or that parameters were adjusted to obtain the reported agreement. Those would be technical criticisms and can be tested directly.

More fundamentally, the label appears to assume that a structure recovered directly from measurements is merely descriptive unless translated into an established theoretical framework. That is an epistemological assumption, not a technical demonstration that the empirical result fails. Whether the reported structure organizes, generalizes, predicts, and compresses the data must be judged from the evidence itself.

“This article …has little physics content”

Across the coordinated package, the result is not merely a fitted relation or an isolated prediction. It is a striking compression of atomic information: the same low-dimensional spectral structure organizes fine spectral behavior, periodic organization, multiple atomic and chemical properties, and quantitative predictions in the heavy and superheavy regime. That degree of empirical compression is itself a physical result.

We therefore expected a technical evaluation of whether the reported structures are real, whether the quantitative relations hold, whether the predictions survive independent tests, and whether the claimed compression is actually present in the data. Instead, the reviewer substitutes an epistemological classification of what is allowed to count as “physics” or as an “explanation” for a technical evaluation of the claims and results.

The statement that the work has “little physics content” is therefore not evidence against the manuscript. It reflects an interpretive assumption about the form that physical understanding must take. The relevant scientific question is whether a closed predictive structure exists directly in the measurements and whether that structure is sufficient to organize, generalize, and predict the observed phenomena. That question has to be answered by examining the evidence, not by defining the result outside physics before evaluating it. We have anticipated and addressed these epistemological arguments separately in a series of non-technical papers (Link). The present paper is about empirical evidence, reproducibility, compression and predictive structure. Replacing evaluation of those claims with a prior debate over what is permitted to count as physics does not constitute a technical assessment of the work.

“The author makes no effort to link his recursive formula for calculating K-edge energies to any meaning about the relativistic Dirac theory with additional corrections”

This is a legitimate and important scientific question that we have precisely addressed in a subsequent paper [link], but it is not the question addressed in the present paper. The purpose of this paper is to demonstrate that the spectral coordinate developed in the companion work permits a very high degree of empirical compression and accuracy in the prediction of K-edge frequencies, replacing complex, computationally intensive multielectron relativistic calculations with a compact predictive relation derived directly from two measured spectral quantities.

Understanding how this compressed empirical law bears on the Dirac–Fock description is nevertheless an important next question, because it concerns what the existence of this empirical compression means for our understanding of the theoretical representation of the same atomic system.

The reviewer’s comment therefore identifies an important next-level question, but it does not invalidate the empirical result reported here. It also highlights the importance of reviewing this body of work as a coordinated package: the individual papers address different but connected levels of the same framework, and evaluating one paper in isolation can make an intentional division of scientific questions appear to be an omission.

“The author presents a fitted formula that he argues (already in the title) as having no "relativistic input". However, the recursive formula starts from the experimental K-edge frequency of atomic xenon, which of course contains relativistic information”

The reviewer assumes that a prediction beginning from an experimentally measured K-edge constitutes “relativistic input” because the measurement is presumed to contain relativistic effects. This conflates a measured physical quantity with a theoretical interpretation used to describe that quantity. The predictive construction uses measured spectral quantities and empirical relations between them; it does not use the Dirac equation, relativistic corrections, relativistic many-electron calculations, QED corrections, or theoretical relativistic quantities as inputs. Interpreting a measured K-edge through relativistic theory does not make that theory an input to an empirical relation constructed from the measurement itself.

The reviewer’s reasoning is circular and unfalsifiable. If relativity is assumed to be embedded in every atomic measurement, then any empirical construction using such a measurement can automatically be described as containing relativistic input, regardless of whether relativistic theory enters the equations or calculation. No empirical result could then demonstrate independence from the theoretical machinery because that independence has been excluded by definition. This grants theoretical interpretation epistemic priority over the measurement itself: the theoretical explanation is assumed to be intrinsic to the observation before the empirical alternative is tested. The argument therefore assumes the very point the manuscript is testing: whether the observed structure and its predictions can be recovered from measurements alone, without relativistic theory as an input.

The relevant technical question is therefore straightforward: what quantities, equations, and parameters actually enter the prediction? Here, the empirical law is constructed from measured spectral quantities and then frozen before prediction. A technical objection would need to identify where relativistic theoretical information enters that mathematical construction or demonstrate that the resulting predictions fail. The subsequent coordinate-mismatch paper (link) strengthens this distinction by showing that the empirical framework predicts not only measured spectral values but also the values obtained by relativistic and quantum calculations without using those theories, and explains where and why the empirical and theoretical predictions diverge.

This objection is therefore epistemological, not a technical demonstration that the empirical prediction fails. We have addressed the broader issue separately in Beyond Representation. Calling an experimental measurement “relativistic input” because relativity can be used to interpret that measurement does not demonstrate that relativistic theory enters the prediction, nor does it provide scientific evidence against the empirical claim.

“In the observables studied here by the author, however, there is already a fundamental theory that is believed with strong evidence to represent our best understanding of K-edge energies.

This is the same theory-first premise that underlies the reviewer’s subsequent claim that an experimentally measured K edge already constitutes “relativistic input.” In the first comment, the existence of the theory is treated as sufficient reason to subordinate the empirical question to that theory; in the second, the theory is treated as intrinsic to the measurement itself. The latter goes further by conflating the measured phenomenon with its theoretical interpretation.

“The author also claims to have a formula that involves only 3 parameters: his constants a and b and the K-edge frequency f(Z0) for atomic xenon with nuclear charge Z0=54. One could argue that there is one more implied fitting parameter, namely the value of Z0=54, above which the fitted recursive formula is claimed to apply.”

The reviewer conflates fitted parameters with fixed empirical quantities.

The coefficients a and b are fitted from the empirical spectral relation, while the recursion is initialized from a measured K-edge frequency (a quantity) at the beginning of the heavy-element regime.

That measured starting condition is not a fitting parameter by any accepted statistical or methodological definition.

“A physicist normally seeks understanding of the mathematical description, something not pursued here. Rather, the fitting formula is the end outcome, which the author argues is all one needs to know or care about”

This comment substitutes the reviewer’s preferred form of explanation for the scientific question actually addressed in the paper. It is therefore an epistemological objection about what is allowed to count as physical explanation, not a demonstration that the empirical structure, its compression, or its predictions fail. The manuscript does pursue mathematical understanding: it identifies a scale-invariant relation between measured spectral quantities, determines its structure, tests its stability, and uses the resulting fixed law to generate quantitative predictions across the heavy- and superheavy-element regime. What it does not require is that this empirical structure first be translated into the conventional microscopic theoretical description before it can count as scientific understanding.

The fitting formula is not the scientific endpoint; the empirical predictive compression it reveals is the result. A remarkably compact structure derived from measured spectral quantities reproduces and predicts K-edge behavior ordinarily approached through complex, computationally intensive multielectron calculations. Across the coordinated package, the same low-dimensional spectral framework is tested for its ability to organize, generalize, and predict phenomena ordinarily treated as separate atomic problems.

The statement that the author argues that the formula is “all one needs to know or care about” is not a claim made in the manuscript. It is an attribution introduced by the reviewer and cannot serve as evidence against the work. The K-edge law is one result within a broader coordinated framework whose structure, generalization, and predictive consequences are examined across the companion papers; it is therefore not presented as the “end outcome.”

The relevant technical evaluation is whether the claimed empirical structure exists, whether it survives independent tests, and whether its predictive compression is real. The reviewer does not demonstrate that any of these claims fail.

“There are predictions for elements where no calculation nor experiment are available. If they are measured and found to agree with the author's formula, the author will argue that it proves the predictive power. Presumably, if a measurement is found not to agree with the author's recursive fitted formula, a new formula will be fitted with perhaps one or more additional parameters in the fit.”

The reviewer conflates two different methodological situations: a theoretical description that may be modified by introducing additional terms or corrections when discrepancies arise, and the empirical relation tested here, whose coefficients are already fixed by existing measurements and whose prospective predictions contain no adjustable parameters.

This distinction is central because the manuscript gives numerical predictions for elements for which, as the reviewer notes, neither calculation nor experiment is presently available. The predictions are therefore fixed before the outcome is known and are directly exposed to future test. There is no element-specific adjustment, residual correction, target-specific scale factor, or remaining free parameter available to force agreement. Agreement within the stated uncertainty supports the law; disagreement outside it falsifies or delimits its domain of validity.

The reviewer’s comment attempts to discredit both possible outcomes of the prospective test in advance. If future measurements agree, the result is dismissed as something the author will merely “argue” demonstrates predictive power; if they disagree, the reviewer “presumes” that the author will alter the formula. This framing discounts prospective success in advance while replacing possible failure with unsupported speculation about future conduct. That speculation is professionally inappropriate and, more importantly, does not address the scientific status of the prediction actually presented, which is already fixed, prospective, and falsifiable.

“The author does not point out that this functional form can be recast as an ordinary function, which I find to be mathematically equivalent, of the following form which would be far more convenient for an interested experimentalist to utilize in practice: f(Z)=(1/(1 - b))^(Z - Z0)*(f(Z0) + a/b) - a/b”

This is an instance in which the reviewer’s counterargument inadvertently demonstrates the paper’s central claim. The reviewer’s reformulation conflates fitted parameters, measured physical quantities, and an ordinal counting index. In the empirical law, a and b are coefficients obtained from the measured relation between Δνmax and νmax; νmax is the measured physical quantity that defines the law; and n is only an integer counter used to propagate the recurrence.

Δνmax = a + bνmax.

Replacing n by Z − Z0, k, p, or any other integer counter changes only the label used to count successive steps; it does not replace νmax as the measured variable that defines the empirical law. For consecutive elements,

Z − Z0 = n − n0,

so Z − Z0 can of course serve as an ordinal counter. But this contains no spectral information. If Z genuinely replaced νmax as the variable defining the law, the corresponding spacing would simply be

ΔZ = 1,

which contains no analogue of the nontrivial, scale-dependent relation

Δνmax = a + bνmax.

Atomic number therefore supplies ordering, not the measured variation in spectral spacing from which the predictive law is obtained. The law was not, and cannot be, discovered as a function of atomic number because Z cannot substitute for νmax.

The reviewer’s reformulation works only because it retains the spectral coefficients a and b, the measured spectral anchor, and the already-established spectral recurrence. The role of Z − Z0 is only to specify how many times that spectral relation is propagated.

The reviewer’s reformulation is therefore not an independent Z-based alternative to the spectral law. A genuine Z-based alternative would have to recover the nontrivial spacing relation and its predictive content from atomic number itself, without importing the spectral coefficients, spectral anchor, and spectral recurrence. The proposed expression does not do that.

Thus, the reviewer’s counterargument demonstrates the opposite of what it appears to suggest. In attempting to replace the spectral formulation by a function of Z, the reviewer can replace only the counting index n with Z − Z0, while the organizing variable νmax, the spectral-spacing relation, and all of the empirical information derived from them remain indispensable. That is exactly why Z cannot replace νmax as the organizing coordinate.

“Here I disagree with the author. This curve fitting exercise is not addressing any fundamental question about the innermost workings of K-shell electrons in heavy atoms.

The reviewer again replaces the scientific question posed by the manuscript with a different one. The paper does not ask for a microscopic account of the “innermost workings” of K-shell electrons. It asks whether the measured K-edge progression contains a low-dimensional empirical structure capable of organizing and quantitatively predicting heavy- and superheavy-element behavior.

Calling that question non-fundamental simply because it is not formulated in microscopic theoretical variables is an epistemological judgment about what is permitted to count as a fundamental physical question, not evidence that the empirical result fails. Whether a remarkably compressed predictive structure exists directly in the measurements is itself a fundamental scientific question, particularly when that structure reproduces behavior ordinarily obtained through complex, computationally intensive multielectron calculations.

Across the coordinated package, the question is broader still: whether the same low-dimensional spectral organization can generalize across fine spectral structure, periodic organization, and multiple atomic and chemical phenomena. That degree of empirical predictive compression is precisely what requires explanation; it cannot be dismissed by redefining “fundamental” in advance to mean only microscopic theoretical mechanism.

The reviewer therefore does not demonstrate that the empirical structure is accidental, that its predictions fail, or that its compression disappears under independent testing. The comment states a preferred conception of fundamental explanation; it does not constitute a technical evaluation of the scientific claim made in the manuscript.

If the author would use the fitted function to learn something about the solution of the many-electron Dirac equation, or various QED corrections, it might conceivably have interest for physicists, but this does not emerge in its present form.”

That is an interesting question, but it is not the question addressed here. This comment extends the same theory-first premise expressed in the preceding objections. The reviewer does not identify a failure of the empirical law, its validation, or its predictions. Instead, he states that the work might have interest for physicists if it were used to illuminate the many-electron Dirac equation or QED corrections.

That requirement reverses the scientific question posed by the manuscript. The work asks whether measured spectral quantities contain sufficient empirical structure to organize and predict heavy- and superheavy-element K-edge behavior without requiring those theoretical constructions as inputs. The reviewer instead assumes that the value of the empirical result depends on its ability to contribute back to those same constructions.

The relevant technical question is therefore not whether the empirical law can be translated into the Dirac equation or QED corrections, but whether the law exists, whether it survives independent validation, and whether its fixed predictions are quantitatively successful and falsifiable. The reviewer does not demonstrate failure on any of those grounds.

The statement that the work would only “conceivably have interest for physicists” if it were connected back to Dirac/QED is therefore not evidence against the empirical result. It is a statement about what kind of result the reviewer regards as physically interesting. If the reviewer is interested to learn about the new insight that this work provides regarding Dirac-Fock and QED corrections, we recommend reading the latest paper that directly addresses that question [link].

“Conclusions Justified?: No,” “To reiterate, I recommend against publication of this manuscript.”

The review recommends rejection under “Conclusions Justified?: No.”

Yet the report does not identify a quantitative failure that would justify that judgment. It does not challenge the reported residuals, uncertainty analysis, cross-validation, parameter stability, held-out predictions, or comparisons with available experimental and theoretical values. Nor does it identify a statistical error, failed prediction, or reproducibility problem, or demonstrate lack of novelty.

The manuscripts provide the complete experimental datasets, equations, fitting procedures, calculations, and uncertainty analyses required to reproduce the work in full. With current computational and AI-assisted tools, the reported results can be independently checked in seconds by simply uploading the manuscript. Yet the reviewer does not identify any quantitative result that is incorrect.

Instead, the negative assessment is directed primarily toward epistemological objections: whether an empirical structure without a Dirac/QED interpretation counts as physics, whether established theoretical representation should be granted explanatory priority, whether theory hides inside empirical measurements, and what form of understanding a physicist is expected to seek.

Those objections do not demonstrate that the conclusions are unjustified. A judgment of “Conclusions Justified?: No” requires identifying where the empirical, mathematical, or quantitative evidentiary chain fails. The reviewer does not do so. The report does not show that the data are wrong, the calculations fail, the uncertainties are mishandled, the validation is defective, or the predictions are quantitatively unsuccessful. This distinction is consequential. Peer review cannot substitute disagreement over what should count as physical explanation for a technical evaluation of whether the evidence supports the claims actually made. Here, the numerical evidence is fully exposed and directly reproducible, while the stated grounds for rejection are directed predominantly toward the epistemological status of the empirical framework rather than a demonstrated failure of its scientific results.

What the review did not directly test
What the referee report does not directly test. The report does not identify a failed cross-validation result, recompute the withheld Pb–U-gap comparison, challenge the stated prediction errors numerically, construct an independently specified competing predictor with comparable compression, or show that the empirical spacing law follows trivially from Dirac/QED theory. Those would be direct tests of the manuscript’s central claims. The response therefore distinguishes disagreement about interpretation from a demonstrated failure of the empirical result.
PNAS 2026-20623 · PAPER 3

Atomic Periodicity as Spectral Structure

Two measured spectral quantities are used to recover period bands, group trajectories, branching transitions, predictive relations, and physical-property organization.
2 referees · rejected
Editorial decision

Editorial decision

The Editorial Board Member stated that the manuscript could not be accepted based on the two reviews and characterized the work as “neither novel nor sufficient to advance at PNAS,” adding that a revised version would not be accepted.

PNAS decision email · Paper 3
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Original PNAS decision email screenshot.

Response to editor

Response to Editorial Comment · Paper 3PDFDownload response PDF

The editor’s stated justification closely tracks Reviewer 1, not Reviewer 2. The decision states that “the two reviews” establish that the work is “neither novel nor sufficient to advance at PNAS.” Yet Reviewer 2 explicitly rated the manuscript Suitable Quality: Yes, Sufficient General Interest: Yes, and Conclusions Justified: Yes, and did not make the categorical novelty judgment attributed to both reports. Reviewer 2 raises serious conceptual objections, addressed separately in the detailed rebuttal, but the report does not support the editorial characterization that both reviewers reached the same fundamental conclusion.

This is consequential because the principal basis for the novelty judgment is itself a mischaracterization of the manuscript’s contribution. Reviewer 1 reduces the work to the familiar proposition that spectroscopy is related to periodicity and therefore declares it non-novel. But that is not the result being claimed.

The novelty is threefold. First, two measured spectral coordinates recover periodic organization quantitatively and turn it into a predictive system. Second, Papers 1 and 3 identify a common empirical architecture linking fine spectral structure (spectral-mode splitting) to periodic differentiation across the elements. Third, the framework achieves substantial predictive compression: the same two-coordinate spectral space organizes and predicts spectral, geometric, chemical, and physical properties from minimal measured input. The manuscript reports leave-one-out median prediction errors of 1.1% for ionization frequencies and 2.1% for covalent radii, while the same coordinate system also organizes conductivity and magnetic behavior.

Neither review directly evaluates these central novelty claims. Reviewer 1 largely bypasses the reported quantitative prediction, cross-observable generalization, and predictive compression. Reviewer 2 accepts the manuscript’s quality, general interest, and justified conclusions, yet dismisses the two-dimensional organization as providing “no further insight” because the spectral coordinates correlate with ZZ. Reviewer 2 then makes a false claim when asserting that an appropriately rescaled ZZ “should make no difference.” The manuscript directly tests that proposition and shows that ZZ does not recover the same organization. The detailed analysis shows that ZZ preserves coarse ordering but fails to recover the residual geometry and recursive branching structure revealed by the K-edge coordinate. The reviewer neither addresses this evidence nor provides a counter-analysis overturning it.

This omission bears directly on novelty. The spectral coordinate does not merely improve a correlation. It reveals a continuous spectral lineage in which mode splitting at the local spectral level and periodic differentiation across elements emerge as parts of the same hierarchical architecture. The coordinated framework therefore connects two major physical phenomena ordinarily treated at different scales: fine spectral structure and periodic organization. The later analysis makes this connection explicit as local and global realizations of the same mode-splitting structure. Neither reviewer identifies prior work establishing this cross-scale unification.

The editor then adopted essentially Reviewer 1’s conclusion, attributed it to “the two reviews,” and categorically excluded revision. I therefore respectfully invite the Editor to examine the accompanying rebuttal and point-by-point responses before allowing that characterization to stand as the final technical assessment of the manuscript. A categorical judgment that the work is “neither novel nor sufficient to advance at PNAS” is difficult to sustain when Reviewer 1 dismisses the work as non-novel by treating it as nothing more than the already-known relationship between spectroscopy and periodicity, a central reviewer assertion is contradicted by evidence already presented in the manuscript, the unprecedented two-coordinate compression of atomic properties was ignored, and the manuscript’s principal quantitative and predictive results were not directly evaluated. I believe the basis for the decision therefore warrants direct editorial reconsideration.

Why this warrants reconsideration. The two reviews do not converge on a single technical finding that the quantitative structure fails. One review substantially changes the novelty question by reducing it to the already-known relationship between spectroscopy and periodicity and ignoring the actual claims made in the paper.  The other accepts the paper’s overall quality and conclusions but interprets the empirical results through a theory-first causal hierarchy, and makes a false claim about the equivalence of ZZ by ignoring evidence in the manuscript showing that ZZ fails to recover the same structure. The point-by-point record below therefore asks a narrower question: which objections precisely falsify or weaken the reported empirical structure and novelty claims?


Reviewer 1 · comment and rebuttal

Reviewer 1PDFDownload point-by-point PDF

Review assessment Summary

The report contains serious internal contradictions and factual inaccuracies, including claims that conflict with or fail to account for evidence explicitly provided in the submission. The referee states that the work “does not break new ground” and merely “re derives a known result,” then later recognizes as valuable the paper’s result of identifying the minimal empirical principles underlying periodicity, asks the author to make that objective explicit, and overlooks that the Introduction already states it directly. The report also claims that statistical validation and correlation metrics are absent, although they are explicitly provided in the Abstract, main text, and Supplementary Information. The referee further alleges selection bias based on a misunderstanding of the validation procedure. The suggestion to include groups containing only three elements in leave one out validation is statistically invalid because withholding one element leaves only two observations for fitting. The rejection therefore relies in substantial part on contradictory novelty judgments, false factual claims, methodological misunderstandings, and failure to account for submitted evidence.

“The paper asserts that the periodic system can be derived directly from atomic observables without prior chemical or theoretical knowledge. However, this is not a new insight.”

The reviewer reduces the paper’s result to the generic observation that spectroscopy contains periodic information. That is not the novelty claimed or demonstrated. The paper identifies a specific two-coordinate spectral structure in which periods form bounded bands, groups form scaling trajectories, and spectral lineage can be followed across successive atoms as continuous modes bifurcate into persistent descendant branches. These splitting events coincide with major periodic boundaries, directly linking the evolution of spectral structure to periodic differentiation. The framework further reveals a quantitative contraction of periodic bandwidth and supports prediction of atomic properties.

If these results are already known, the reviewer should identify prior work demonstrating this spectral lineage, its recursive mode splitting at periodic boundaries, the two-coordinate scaling geometry, quantitative bandwidth convergence, and the resulting predictive relations. No such literature is cited. General references showing that spectroscopy contains periodic information do not establish prior discovery of these results.

“The historical development of the periodic system followed a trajectory: S → P → A, where S = spectroscopic and chemical data, P = periodic system, and A = atomic theory (e.g., quantum theory). The current work demonstrates S → P, which is well known and has been repeatedly shown in both historical and computational studies. The reverse path (A → P → S) is what quantum theory enables. Thus, the paper does not break new ground but rather re-derives a known result.”

This comment contains two distinct inaccuracies: a historical inaccuracy in the proposed S → P → A sequence, and a conceptual mischaracterization of what the present work demonstrates.

First, the historical sequence is inaccurate. The periodic system was established primarily from recurring chemical properties and atomic weights, not from spectroscopy. The manuscript explicitly distinguishes these stages: periodic organization was identified first from elemental properties, while spectroscopic regularities were recognized subsequently and later interpreted within atomic theory. Combining “spectroscopic and chemical data” into a single historical category S therefore conflates distinct stages in the development of the periodic system.

Second, describing the present work simply as S → P removes almost everything the paper actually demonstrates. Using only two directly measured spectral frequencies, the framework recovers the chemical grouping of the periodic system and reveals additional groupings associated with physical properties such as conductivity and magnetism, with each group following its own quantitative scaling law that can be used predictively. It also reveals spectral lineage and recursive mode splitting associated with periodic differentiation, quantifies the contraction of periodic structure across the table, and generates predictions of atomic and material properties.

Calling all of this simply “S → P” is therefore not a substantive description of the work. Recovering a known classification from data is one thing; showing that two measured frequencies define a quantitative system that organizes chemical and physical behavior, reveals the structure and evolution of periodic differentiation, and generates predictions is another.

If the reviewer considers these specific results, including the empirical scaling laws and prospective predictions, to have been “repeatedly shown,” then the relevant prior literature demonstrating them should be identified.

“The claim that "the periodic system was established from trends in atomic weight and chemical behavior and later explained through electronic structure models, but it has not been derived directly from atomic observables without prior chemical or theoretical knowledge" is historically inaccurate:
• The periodic system emerged from empirical observations of chemical reactivity and substance behaviour.
• Recent data-driven studies (e.g., in PNAS) have shown that the periodic system can be reconstructed from chemical data alone.
• Historians such as Michael Gordin (on Mendeleev) and Alan Rocke & Gisela Boeck (on Meyer) have demonstrated that theoretical and chemical frameworks were essential to the system's formulation.
Therefore, the claim that the system was "devised without chemical or theoretical knowledge" is incorrect.”

The reviewer appears to have misread the manuscript: most of the historical claims presented here as objections actually agree with the paper, while the concluding criticism attributes to the manuscript a claim that it does not make.

First, the historical criticism is directed at a statement that is not in the paper. The manuscript states that the periodic system was established from empirical trends in atomic weight and chemical behavior and was later interpreted through models of atomic structure. The reviewer’s statements that the periodic system emerged from chemical behavior and that chemical frameworks were important to its formulation therefore do not contradict the manuscript; they largely restate it.

The reviewer then concludes that the manuscript claims the periodic system was “devised without chemical or theoretical knowledge.” That is not what the manuscript says. The phrase “without prior chemical or theoretical knowledge” refers to the objective of the present work: whether periodic organization can be derived directly from measured atomic observables without using chemical classification or theoretical structure as input. It is not a historical claim about how the periodic table was devised. The criticism therefore changes the meaning of the manuscript’s statement and then rejects that altered version.

Second, reconstructing the periodic table from chemical data is not equivalent to what is done here. A data-driven reconstruction from chemical properties still begins with chemical information. The present work instead asks whether periodic organization emerges from a coordinate system defined by only two directly measured spectral frequencies, and whether that same empirical structure yields quantitative scaling laws, physical-property groupings, periodic differentiation, and predictions. The manuscript shows that the resulting spectral space recovers periods and chemical and physical groups, reveals recursive spectral branching and periodic contraction, and provides a quantitative basis for prediction.

The historical observations cited by the reviewer therefore do not refute the manuscript, and reconstruction from chemical data addresses a different question. The central claim is whether periodic organization can be derived, quantified, and predicted directly from atomic observables without supplying the chemical or theoretical structure in advance.

“The core message that the paper attempts to identify the minimal empirical principles underlying periodicity is valuable and deserves clearer articulation. However, this goal is currently buried in the text. The manuscript should explicitly state this objective early on and frame the analysis accordingly. This would align the work with ongoing debates about the minimal dimensionality of the periodic system and the role of data-driven discovery.”

This comment is difficult to reconcile with the reviewer’s preceding criticism. The reviewer previously characterized the work as merely reproducing the known relation S → P and therefore lacking conceptual novelty, but here explicitly recognizes the attempt to identify the minimal empirical principles underlying periodicity as valuable and relevant to questions of minimal dimensionality and data-driven discovery. That is precisely the broader objective of the work that the preceding criticism overlooks.

The requested clarification is also already present in the manuscript. The Introduction explicitly states: “Reexamining periodicity in the spectral domain is an attempt to identify the minimal empirical principles from which periodic organization of the elements can be explained, quantified and predicted.” This statement appears before the analysis and directly frames what follows.

The issue is therefore not that the objective was absent, but that the reviewer’s earlier assessment did not evaluate the work according to the objective that the reviewer here correctly identifies.

“The exclusion of groups with fewer than three elements (n = 3) is problematic. Many transition metal groups (e.g., Cr, Mn, Fe) consist of only three elements. By excluding them, the analysis implicitly favors main-group elements, which are more chemically homogeneous and stable. This introduces a selection bias and undermines the claim of a "general" derivation of periodicity.”

This criticism is based on a clear factual misreading of the Methods. Groups with three members were not excluded from the analysis of periodic structure. The structural analysis spans the periodic groups across the table, including Groups 1 and 2, transition-metal Groups 3–12, and Groups 13–18. The manuscript explicitly analyzes the transition metals and shows that Groups 3–12 form distinct scaling trajectories in the same spectral coordinate system.

The n = 3 restriction cited by the reviewer applies only to the leave-one-out cross-validation of predictive relations. In that procedure, withholding one element from a three-member group leaves only two points for fitting. Those groups were therefore excluded from that specific predictive cross-validation, not from the structural analysis of periodicity. The Supplementary Methods explicitly state this restriction in the section describing the cross-validation procedure.

The reviewer has therefore attributed to the main analysis an exclusion that does not exist. The subsequent claims that the analysis favors main-group elements, introduces selection bias, and thereby undermines the generality of the periodic derivation all follow from this incorrect premise.

Moreover, the reviewer’s criticism effectively asks that three-member groups be included in a leave-one-out validation where withholding one element leaves only two observations for fitting. Such a procedure would be statistically invalid: a regression fitted to two remaining points cannot provide a meaningful test of predictive performance. The n = 3 restriction is therefore not a source of selection bias but a necessary safeguard against an invalid validation procedure. It has no bearing on the inclusion of these groups in the structural analysis.

“The section on predictions is interesting, but the claims are not supported by statistical validation. For example, the prediction of superconducting behavior in Cr and Ag lacks a quantitative analysis of experimental data. To strengthen the work, the author should compare predictions with those from quantum chemistry and assess whether the statistical model offers explanatory power beyond existing theoretical frameworks.”

This criticism conflates two different types of prediction and incorrectly states that the manuscript lacks statistical validation.

The principal quantitative predictions are explicitly cross-validated, and the results are reported in the Abstract itself. Leave-one-out validation yields median prediction errors of 1.1% for first-ionization frequencies and 2.1% for covalent radii, with errors below 0.3% for the lanthanide-series predictions. The statement that the prediction claims “are not supported by statistical validation” is therefore directly contradicted by the manuscript.

The Cr and Ag superconductivity statement is a separate qualitative prospective prediction, not the basis of the quantitative validation. The reviewer selects this secondary example and uses it to characterize the entire prediction analysis while ignoring the explicit cross-validation.

The demand for comparison with quantum chemistry also changes the question being tested. This work asks what can be predicted directly from measured spectral observables without supplying a theoretical model as input. Predictive validity is therefore tested against withheld or independently measured data, not by requiring agreement with a theoretical framework.

The reviewer thus overlooks the statistical validation reported in the Abstract itself, substitutes a secondary qualitative prediction for the quantitative analysis, and imposes a theoretical benchmark that is not required to test the empirical claim.

“Terminology: The manuscript does not clearly distinguish between "periodic table" (a tabular representation) and "periodic system" (a conceptual framework). This ambiguity should be clarified.”

The distinction is understood, but it does not create an ambiguity in the analysis. “Periodic system” appears only once in the manuscript’s substantive text, in the opening sentence of the Abstract; the remaining occurrences are in cited reference titles. Throughout the manuscript, “periodic table” refers to the empirical organization and classification of the elements, not merely to its tabular graphical representation.

For terminological precision, “periodic system” can be used when referring to the conceptual organization of the elements and “periodic table” when referring specifically to its tabular representation. This terminology does not affect the analysis, results, or conclusions.

“Overgeneralisation of periodicity: The claim that "elemental properties recur in a regular pattern" is not universally supported. Recent literature (e.g. in Chemistry - A European Journal) has challenged the regularity of periodic trends, particularly for transition metals and heavier elements. This should be acknowledged.”

This criticism conflates periodic recurrence with the claim that every elemental property follows a perfectly regular monotonic trend. The manuscript makes no such claim.

A central result of the paper is precisely that periodic organization is not described by a single uniform trend, but by distinct spectral scaling regimes. Groups 1–2 and 13–18 form the principal set of nearly parallel, converging trajectories, whereas transition-metal Groups 3–12 define a second family with weaker slopes and local expansion within the d-block. The manuscript further resolves deviations from nominal group trajectories and piecewise regimes within the lanthanides and actinides. Identifying this structured coexistence of convergence, local expansion, and group-specific departures in the same two-coordinate spectral space is part of the novel empirical result.

The behavior of heavier elements is likewise not ignored. The manuscript quantitatively shows that periodic spectral bandwidth contracts with increasing νmax, causing group trajectories to become progressively compressed and less distinguishable in the lanthanide and actinide regions. Thus, the weakening and blurring of conventional periodic trends in heavy elements is not a counterexample to the framework; it is itself a measured feature of the spectral structure that the paper identifies and quantifies.

More fundamentally, recurrence does not require every local trend to be smooth or exception-free. A subsequent empirical analysis addresses recurrence directly and shows that it follows a quantitative spectral scaling law within the same two-coordinate space [link].

The literature cited by the reviewer may challenge simplistic or universally monotonic formulations of periodic trends, but that is not the formulation used in this manuscript. The present work instead reveals a more structured form of periodicity in which recurrence coexists with distinct scaling families, local deviations, and progressive loss of differentiation, and those features are themselves among the paper’s principal empirical findings.

“Subjective interpretation of physical properties: Statements such as "electrical conductivity and magnetic behavior align along distinct diagonal branches" are qualitative and lack quantitative support. No statistical analysis or correlation metrics are provided. These claims should be either removed or substantiated with data.”

This criticism is factually incorrect. The statistical analysis and correlation metrics that the reviewer states are absent are explicitly provided in the Supplementary Information and directly cited in the corresponding main-text passage.

Immediately after stating that electrical conductivity and magnetic behavior align along distinct spectral branches, the manuscript states that these branches resolve the different physical-property classes “with high statistical significance (Table S3).” Table S3 reports the regression slopes, Pearson correlation coefficients, R2, adjusted R2, residual sums of squares, degrees of freedom, number of observations, root MSE, and normalized residuals for the conductivity and magnetic branches. The reported correlations are approximately |r| = 0.998 to 1.000, with R2 values of approximately 0.996 to 1.000.

The superconducting branch is also tested separately in Table S4 using three different elemental compositions, yielding R2 = 0.9971, 0.9971, and 0.9982.

The reviewer therefore labels the result “qualitative” and states that “no statistical analysis or correlation metrics are provided” despite the main text explicitly directing the reader to the statistical analysis and the Supplementary Information reporting precisely those metrics. The request that these claims be “substantiated with data” asks for analysis that is already present in the submitted manuscript.

“Singularities and scaling: The exclusion of first-period elements (B, C, N) due to deviation from the scaling branch is a valid point. The author should consider referencing the "singularity principle" of the periodic system, which addresses such anomalies.”

The reviewer correctly notes that the first-row deviations are a recognized feature of the periodic system and suggests the “singularity principle” as a related conceptual description.

The deviation of these elements is not treated as an inconvenient anomaly to be discarded from the spectral framework. It is itself part of the empirical structure revealed by the analysis.

The anomalous behavior of B, C, and N emerges directly from the same two measured spectral coordinates, without supplying prior chemical knowledge.

The reviewer suggests invoking the “singularity principle” as an existing conceptual description of such first-row anomalies. That literature may provide historical or chemical context. However, invoking an established name for the anomalous behavior does not explain the empirical spectral result reported here.

The relevant distinction is between recognizing that first row elements are anomalous, which is already known, and showing that this anomaly emerges independently and quantitatively within the newly identified spectral structure. The latter is the result of this work.

Reviewer 2 · comment and rebuttal

Reviewer 2PDFDownload point-by-point PDF

Review assessment Summary

Unlike the other reviews, this report is not adversarial in tone and shows an evident effort to engage objectively with the work. Most importantly, the reviewer explicitly acknowledges the central empirical result: that statistical analysis of purely empirical atomic spectral data recovers the two-dimensional organization of the periodic table of chemical elements. This is precisely the principal result reported in the manuscript.

The main issue of the report is relying on epistemological rather than technical evaluation, as observed in the other reviews of the package as well. Several objections substitute theory-first assumptions for evaluation of the empirical framework, including the presumed primacy of Z, configuration averaged energies, S,L,J descriptions, and the proposed theoretical “triangle.” These assumptions are repeatedly invoked despite the manuscript demonstrating with empirical evidence that such theoretical constructs are not used nor required to recover the observed organization. Overall, the reviewer acknowledges the principal empirical finding but repeatedly reinterprets it through the conventional theoretical framework whose necessity the work was designed to test.

“The main problem is that the author's writing style is difficult for ordinary researchers, users, educators, and philosophers of chemistry to read and understand, and is unlikely to lead to many citations, which would be a pity. However, the author can probably hardly change his style.”

This comment does not identify a specific problem with the scientific argument or a particular passage that is unclear. Instead, the reviewer offers a subjective judgment about writing style, speculates about future citation impact, and further speculates that the author is unlikely to be able to change his style.

Some of the perceived difficulty may arise from the unfamiliarity of the framework itself. The analysis deliberately asks the reader to remain in the frequency domain and examine the organization that emerges directly from measured spectral observables, rather than immediately translating those observations into the conventional language of energy levels, electronic configurations, particles, and interactions. The manuscript also introduces several new spectral concepts and relationships needed to describe structures that emerge from this representation. These concepts necessarily require the reader to become familiar with terminology and relationships that are not part of the conventional description of atomic structure.

If specific passages are difficult to understand, they should be identified so that their clarity can be assessed and improved. A general judgment about the author’s writing style, anticipated citation impact, or presumed ability to change his style does not constitute a scientific criticism of the work.

“There is a triangle: at the top is causative general theoretical physics. It determines atomic vacuum physics, and partially understandably the chemistry of materials. Trivially there is a relation between the two ‘lower’ points, which is investigated by the present author. The basic causing parameter is Z, which is here replaced by the K-edge – a conceptual improvement or correction is recommended, see below.”

This comment reflects clearly the epistemic assumptions recurrent throughout the reviews, and that are preventing a technical evaluation of the package. The reviewer assumes in advance the theoretical hierarchy that the manuscript is explicitly testing. The framework does not ask what conventional atomic theory identifies as the basic causal parameter. It asks whether organization can be recovered directly from measured spectral observables without using atomic number or theoretical structure as input. The paper thus cannot be correctly evaluated if the question it is testing is considered in advance by the reviewer as the ground truth.

Atomic number Z and νmax are not alternative variables of equivalent status in this analysis. Z is an externally assigned discrete index used to label and order elements, whereas νmax is a directly measured physical property of each atomic system. The question is therefore not whether νmax is a better proxy for Z, but whether relationships among measured spectral observables reveal an intrinsic organization that is obscured when the systems are represented through an external index.

A monotonic relationship between Z and the K edge does not make them interchangeable coordinates. A measured observable can contain relational structure that is lost when it is replaced by an ordinal index correlated with it. Paper 3 tests this directly: replacing νmax with Z preserves coarse ordering but does not recover the same branching structure and spectral organization.

The reviewer therefore substitutes a theoretical premise for the empirical question being tested. The submitted work asks whether the measured spectral coordinate carries organizational information that Z does not, and the evidence reported shows clearly that it does (Compare Figure 4 with Figure S11, See also Figure S10).

“The next most important variable in low-energy atomic physics and in materials chemistry is the characterization of the so-called electron configuration. In the case of atomic physics, the author opted not for configuration-averaged energies, but rather for the values that are most easily obtained from the NIST database without requiring any theoretical background. A more educated approach would most probably improve the author’s correlations.”

The reviewer again asks the manuscript to reintroduce theoretical constructs that the analysis deliberately excludes. The choice of directly measured NIST frequencies is not a shortcut taken because they are “most easily obtained”; it is the methodological condition being tested. The Materials and Methods section in Supplementary Information clearly outlines this methodology and explains the rational. The foundational paper explicitly removes atomic numbers, quantum numbers, orbital assignments, and term symbols and analyzes the data exclusively in frequency space to determine whether organization emerges from the measurements themselves.

Configuration averaged energies would answer a different question because they already incorporate a theoretical representation of electronic structure. Using them would therefore compromise the strictly empirical test rather than make it “more educated.”

The relevant issue is not whether a theory informed variable might improve a correlation. It is whether two directly measured spectral observables are already sufficient to recover periodic organization and support prediction. Paper 3 demonstrate that they are.

The unprofessional phrase “a more educated approach” is also not a methodological argument.

“The elements of atomic physicists are free unperturbed atoms in physical vacuum, while the elements of chemistry are bonded atoms in chemical substances. An ‘idealized’ rule (that holds in ca. ¾ of all cases) on the neutral atomic orbital occupation at the independent electron approximation when going from element Z to Z+1 was given by Madelung before WW2. After WW2, introductory chemistry textbook authors invented a similar rule, but for going for a given elemental charged atom Z+q to Z+q−1, and labelled that different rule also by the name of Madelung.
Another point is that, in particular for the d and df blocks of elements, the dominant “atomic electron configuration” is often different from the electron configuration, from which the ground level of the free atoms can be derived in the one-electron approximation. I tend to distinguish between different concepts such as state, level, term, and configuration. – Some experts of transition element chemistry know this and use the configuration averaged ionization energies. However to derive them from NIST data, a bit of work, and some knowledge of atomic electronic structure and often some crude estimation of missing data is required. Then the irregularities of the ground levels of open-shell atoms disappear. Example: the naively used atomic first ionization energies IE (listed in ‘all’ Periodic Tables, introductory chemistry textbooks, and used by the present author) of atoms N and (more electronegative) O are larger for N and smaller for O (!); while the respective configuration-averaged IEs increase as smoothly as many other chemical properties of the elements. The present author should mention that the so-called Madelung irregularities are a problem of the basic chemistry textbooks, and of chemically non-bonded atoms, but do NOT appear in realistic chemistry.”

The distinction between free atoms and atoms in chemical substances does not contradict the manuscript. The question being tested is whether measurements of free atoms contain sufficient structure to recover periodic chemical organization. The result is that they do. The manuscript does not claim that isolated and bonded atoms are physically identical.

The extended discussion of Madelung rules, configurations, terms, levels, and configuration averaged ionization energies again introduces theoretical structure that the analysis deliberately excludes. Replacing directly measured first ionization energies with configuration averaged quantities would change the scientific question from whether periodic organization emerges directly from measurement to whether theoretically classified and processed quantities reproduce familiar periodic trends.

The manuscript also directly addresses the supposed Madelung irregularities. Elements conventionally treated as Madelung exceptions do not appear anomalous in the empirical spectral relations. Groups 6 and 10 form statistically coherent scaling relations, with Cr, Mo, W, and Pd aligning on their respective branches without detectable deviation. The relevant regressions retain R2 > 0.998.

The disappearance of these apparent irregularities is therefore a natural finding of the empirical spectral structure itself, not the result of configuration averaging or theoretical regularization. Relationships treated as exceptions under orbital filling heuristics emerge as regular relationships when the organization is derived directly from measured spectral observables.

The reviewer’s discussion of how Madelung irregularities should be interpreted in chemistry textbooks may be relevant to chemical pedagogy, but it does not identify a methodological or empirical failure in the analysis presented here.

“The nuclear charge Z is the basic physical parameter that determines the properties of free atoms in physical vacuum, as well as of the bonded atoms in chemical substances. Since Moseley we know about the smooth relationship between the K-edge and the element number Z. The relation is of the type of the square of a power expansion in Z which diverges (in realistic relativistic quantum physics) for large Z. Hence the statement that the empirical K-edge works better than Z is simply due to the author’s simplistic implicit linear scaling.
p.2 (and later, e.g. p.9 bottom): “Substituting atomic number for Kedge does not reproduce this organization” – requires a simplistic scaling, otherwise there should be no difference. – You may add the “triangle” relationship mentioned above.”

The reviewer again assumes the proposition that this body of work is designed to test: that Z must be the fundamental organizing coordinate of atomic structure. That assumption cannot be used as the ground truth for evaluating a framework whose central empirical question is whether atomic spectral organization and prediction require Z at all. It is an unusual question, but it is nonetheless a fundamental scientific question.

The manuscript removed quantum mechanical annotations from the spectral dataset and asked whether organizational principles could emerge directly from frequencies. It compared νmax based and Z based representations and tested whether the resulting coordinate constrained spectral lineage, bandwidth, fine structure, K edge spacing, isotope multiplicity, and hydrogen series organization. The preference for νmax is therefore a result of the analysis, not an assumption used to construct it.

The submitted work shows directly that the two coordinates are not empirically interchangeable. Supplementary Figures 4 and S11, and Figure S10 directly compares νmax based and Z based scaling for ionization frequency and covalent radius. The νmax representation gives higher R2, lower normalized RMSE, and complete atomic coverage, whereas the Z representation leaves 7 to 8% of atoms ungrouped. Supplementary Fig. S11 shows the deeper structural difference: when the pooled high frequency spectra are represented as ν/Z versus Z, the recursive branching structure observed in ν/νmax versus νmax disappears. The manuscript explicitly identifies this branching structure with spectral lineage and the formation of period boundaries. Fig. S9 further shows that Z can preserve coarse periodic band differentiation, demonstrating that the distinction is not simply one of elemental ordering. Paper 1 of the package provides further evidence of the curvature caused in the data by using Z.

The reviewer’s assertion that with a different scaling “there should be no difference” is therefore not a demonstrated result, and ignores the empirical evidence provided. It is contradicted by the direct coordinate comparisons already provided in the Supplementary Information. A smooth relationship between Z and the K edge does not make them equivalent coordinates or guarantee preservation of the spectral geometry, scaling relations, branching structure, or lineage.

The claim that this difference results from “simplistic implicit linear scaling” is also incorrect. The framework is built from power law and piecewise power law relations across multiple levels of spectral organization. Paper 1 shows that indexing the same frequencies by Z introduces systematic curvature and fails to recover the spectral lineage and fractional spacing law recovered with νmax. Hydrogen provides an independent demonstration that the spectral coordinate cannot simply be reduced to Z: relational spectral organization persists across hydrogen spectral families while Z remains fixed.

The reviewer’s argument concerning divergence at large Z also does not invalidate the empirical coordinate. The submitted companion paper examines the high frequency regime and finds that the empirical K edge spacing law remains stable even as divergence from Dirac Fock reference values increases. The fractional spacing approaches a stable asymptotic limit, with smooth residuals and no corresponding breakdown of the empirical law.

A subsequent study, not included in the submitted package and therefore outside the scope of the present rebuttal, examines and explains the growing divergence between empirical spectral predictions and theoretical (relativistic and quantum) predictions at high Z [link].

The reviewer therefore assumes the necessity and equivalence of Z where the submitted work explicitly tests both propositions. The empirical comparisons show that Z preserves coarse ordering but does not preserve the full spectral organization recovered with νmax.

“p.5: The deviations from linearity, such as the 2-3-3 pattern for Li-Ne, etc., are attributable to the SLJ splitting of open atomic shells, which the author overlooked. Naturally, correcting this would entail a considerable amount of work. However, the author could at least address the second period and add a corresponding note.”

The reviewer again introduces a conventional theoretical description into an analysis whose stated purpose is to remain exclusively in the empirical frequency domain. The present work does not attempt to classify the observed structure in terms of S, L, and J, because such theoretical assignments were deliberately excluded from the analysis from the outset.

Within the empirical frequency domain, periodic differentiation is organized through spectral lineage generated by spectral mode splitting. The results show that major splitting events occur at period boundaries, where they are associated with sharp drops in first ionization frequency, while additional splitting within periods accompanies finer changes in chemical organization, including transitions between transition metal and post transition regions.

For the second period deviations referred to by the reviewer, the available empirical spectral data do not show corresponding resolved spectral splitting events at those specific elements. This does not exclude the possibility that additional minor splittings exist but are unresolved in the available high frequency spectral data.

The relation between spectral splitting and the sharp drops in νion was examined quantitatively in a subsequent study of periodic recurrence [link], which is outside the scope of the present paper. That study shows that the ionization frequency reset at each experimentally measured period boundary is quantitatively linked to the corresponding spectral splitting amplitude, and also identifies additional minor splitting events associated with smaller changes in νion.

The reviewer’s S,L,J description is therefore outside the empirical question addressed in this work, not a correction to it. The present paper asks how periodic differentiation is organized directly in measured frequency space, and the observed organization is expressed through spectral lineage and spectral mode splitting.

“p.10: “The NIST data base does not report K edge experimental lines for elements between Bi and Th.” Mention that this trivially due to the short live times of these elements”

The statement in the manuscript is deliberately limited to the empirical data availability: the NIST database does not report experimental K edge lines for the elements between Bi and Th. The reviewer’s attribution of this absence simply to the short lifetimes of these elements is an interpretation of why the measurements are unavailable and is not required for the empirical analysis. The manuscript therefore reports the actual limitation of the available dataset without assigning a cause that is not established by those data. Again, the methodological discipline in this empirical work is to avoid any theoretical data or interpretation.

“p.13: A reference to the mentioned “companion paper” should be specified.”

The companion paper is already explicitly specified as reference 20 immediately following the statement cited by the reviewer. Reference 20 provides the full title, author, ChemRxiv citation, DOI, and publication year.

This comment also illustrates why coordinated review of the submitted paper package was necessary. The papers were submitted as a connected body of work, with companion studies explicitly cross referenced where their results are used. A coordinated review would have allowed the relationship between the papers and their respective results to be assessed directly, rather than treating an already specified companion paper as though it had not been identified.

“p.15: One may mention that the so-called Madelung anomalies are largely a problem of and created by educational chemistry, it does hardly exist in chemical reality.”

We agree with the reviewer on this point. However, the manuscript already states this interpretation explicitly, not as an assumption but as a conclusion drawn from the empirical spectral evidence. It states:

“the Madelung exceptions no longer manifest as anomalies when the organizing principle is derived from empirically measured spectral relations.”

The manuscript then states:

“the absence of anomalies indicates that the irregularities may arise from the orbital-filling heuristic rather than from discontinuities in the underlying atomic energy structure.”

The point requested by the reviewer is therefore already explicitly stated in the manuscript and, more importantly, is supported as a result of the empirical analysis rather than introduced as an assumption.

“p.16: One should add, that the statistical analysis of purely empirical free atomic SPECTRAL data supports the two dimensional structure of the periodic table of CHEMICAL elements, without any further insight, except that K-edge and first IE of the atoms strongly correlate with Z and average configuration energy requiring some theoretical insight and clever scaling.”

The reviewer here acknowledges the central empirical result of the paper: that statistical analysis of purely empirical atomic spectral data recovers the two-dimensional organization of the periodic table of chemical elements.

The subsequent qualification that this provides “without any further insight” because the K edge and first ionization energy correlate with Z and configuration energy does not follow from that result. Correlation with Z does not establish that Z is the intrinsic organizing coordinate of the spectral structure. Paper 1 in the submitted package directly shows that indexing the same spectral data by Z introduces systematic curvature and fails to recover the spectral lineage and fractional spacing law obtained with νmax.

A subsequent study, not included in the submitted package, further examines how indexing atomic spectra by Z produces a growing displacement at high Z: [link]

The reviewer therefore recognizes the empirical recovery of periodic structure, but continues to interpret that result through the prior assumption that Z must be the fundamental atomic coordinate. The submitted work specifically tests that assumption and finds that Z functions as an external integer index, whereas the measured spectral coordinate preserves structural relationships that Z does not.

“I would reformulate the statement “The periodic table is therefore not an imposed classification but the macroscopic manifestation of this branching spectral structure within a single bounded system.” Namely, in the conceptual triangle mentioned above. General physics determines both empirical subfields of atomic vacuum spectroscopy and elements in chemical compounds. The latter field generates a two-dimensional multiply-connected structure, which trivially happens to correlate with the respective structure in atomic spectroscopy. If one knows, what one wants, one can easily find the two generating variables.”

The proposed reformulation would replace the empirical conclusion of the paper with the reviewer’s assumed theoretical hierarchy. The result of the analysis is precisely that the organization of the periodic system emerges directly from a coordinate defined by two measured atomic frequencies, without requiring atomic number, electron configurations, or the theoretical machinery invoked by the reviewer. The same empirical spectral structure recovers periods and groups, explains periodic differentiation, organizes chemical and physical properties, supports quantitative prediction, and explains specific physical behavior, including why mercury is liquid and why gadolinium exhibits anomalous ferromagnetic behavior.

Nor can the conventional theoretical variables simply be assumed to be hidden inside the empirical measurements, as suggested elsewhere in reviews of this package. The submitted studies explicitly test alternative representations and show that replacing the measured spectral coordinate with Z does not preserve the same spectral organization.

Calling the correspondence between atomic spectroscopy and chemical organization something that “trivially happens to correlate,” or suggesting that the generating variables are easily found “if one knows what one wants,” does not account for these results and does not represent a technical argument. The organization, explanation, and prediction emerge from the measured spectral coordinates themselves. Reintroducing conventional theoretical interpretations after the empirical structure has been discovered does not demonstrate that those interpretations were required to obtain it.

What review did not test
What the review did not test. The manuscript reports leave-one-out prediction of first-ionization frequencies and covalent radii, cross-observable preservation of the spectral organization, a measured contraction of periodic bandwidth, and a branching analysis linking spectral bifurcations to period boundaries. The reviews devote much more attention to whether conventional theory can interpret these observations than to whether the reported quantitative tests themselves succeed. A theory being capable in principle of calculating an observable is not the same question as whether a two-observable empirical structure achieves comparable organization and prediction with far less input. That predictive-compression claim requires direct evaluation.
AUTHOR COMMUNICATION

Rebuttal / request for independent coordinated technical assessmentPDFDownload PDF

Subject: PNAS Spectral Framework package submission: review record and request for independent technical assessment

Dear Editors,

I am writing regarding the three coordinated Spectral Framework manuscripts submitted as a package to PNAS (Paper 1: 2026-20598, Paper 2: 2026-20616, and Paper 3: 2026-20623), on June 11, 2026.

Interactive PNAS peer-review record [link]: The linked site provides the complete review record, including the editorial decisions, reviewer reports, point-by-point responses, and the empirical and mathematical evidence associated with each disputed claim. All files are also attached by email to this letter, including a proposed change to the submitted package structure and suggested review criteria.

The sole reviewer of Paper 2 (2026-20616) summarizes the concerns with the reviews received and the editorial decisions based on them. Faced with falsifiable prospective predictions, the reviewer states:

“There are predictions for elements where no calculation nor experiment are available. If they are measured and found to agree with the author’s formula, the author will argue that it proves the predictive power. Presumably, if a measurement is found not to agree with the author’s recursive fitted formula, a new formula will be fitted with perhaps one or more additional parameters in the fit”.

In addition to speculating about the author’s future conduct, and labeling the work as curve-fitting without identifying a single failure, the reviewer conflates two different situations: a theoretical relation that may be revised by introducing additional terms, and an empirical relation (this work) already fixed by existing measurements, with no free parameters. More concerning, the reviewer’s comment undermines the logic of falsifiability by pre-emptively discrediting both possible outcomes of a prospective quantitative test. The same reviewer further asserts that the paper “contains little physics,” while simultaneously claiming that “physics (theory) is contained” in the empirical measurements themselves.

These comments are particularly revealing of the epistemic framing in which the papers were reviewed. Empirical evidence is either ignored or dismissed by a theory-first narrative of curve fitting and “theory hidden in the measurements,” even when no theoretical input is used. This mode of reasoning, recurrent throughout the reviews, insulates the preferred theoretical interpretation from empirical challenge and renders any proposed alternative dismissible by construction, irrespective of the evidence.

After examining the three decisions and reviewer reports together, I believe the difficulties encountered by both editors and reviewers during evaluation arise from two related issues: the requested coordinated review of the three-paper package does not appear to have occurred, and the majority of reviewer comments appear to assess the empirical framework, not by technical analysis of the evidence and claims but through epistemic judgements and conventional theoretical assumptions, at a time when the package’s central claim is that those theoretical constructs are neither used nor required.

1. Editorial concern

In our cover letter, we explicitly requested coordinated review of the three-paper package because the manuscripts are empirically and conceptually interdependent. Paper 2 was evaluated by a single reviewer, Paper 3 by two different reviewers whose reports do not indicate awareness of the companion manuscripts, while Paper 1, the foundational manuscript introducing the framework on which the companion studies build, was rejected without external expert review because, according to the editorial decision, “the editor found this paper very confusing and not understandable.”

This is consequential. A manuscript containing evidence needed to evaluate objections subsequently raised against the companion papers was not subjected to technical scrutiny of its data, methods, mathematics, or conclusions, but was instead declined at the editorial stage because its framework was not understood. Several objections raised in the other reviews concern precisely the empirical organization established in that foundational paper. Claims raised in one review could have been evaluated against evidence contained elsewhere in the submitted package. The attached response to editors and interactive review record address the comprehensibility issue directly.

Another editorial issue is related to the editorial decision on Paper 3. The editor’s decision states that “the two reviews” establish that the work is “neither novel nor sufficient to advance at PNAS.” Yet the report does not support the editorial characterization that both reviewers reached the same fundamental conclusion. More concerning, the reviews that claimed lack of novelty contain serious internal contradictions, method and claim mischaracterization, and factual inaccuracies, including claims that conflict with or fail to account for evidence explicitly provided in the submission (see point by point response to the editor and reviewer comments).

2. Conceptual concern

The reviewer’s statement that the work “contains little physics” identifies precisely the conceptual issue. If “physics” is restricted to relationships among particles, forces, and inferred mechanisms, then the work presented here is indeed different. These papers do not propose a new microscopic theory. They demonstrate a scientific methodology for identifying an empirical layer of organization underlying atomic physics and chemistry directly in measurement space without requiring theory.

The manuscripts ask the reader to temporarily set aside the conventional explanatory hierarchy of atomic physics and chemistry and first examine spectral data as an empirical geometric and scaling system.

The conventional theoretical thinking follows:

theoretical model → Hamiltonian → states/orbitals → transitions → spectra

The Spectral Framework deliberately begins in the opposite direction:

empirical measurements → spectral coordinates → scaling relations and invariants → organization, prediction, and explanation

Theoretical interpretation is therefore deliberately downstream of the first empirical question: whether a closed predictive structure exists directly in the measurements and whether that structure is sufficient to organize, explain, generalize and predict the observed phenomena. This distinction matters because several reviewer criticisms ask for explanations in terms of shells, electronic configurations, energy levels, Dirac theory, or QED at precisely the point where the manuscripts are demonstrating with evidence that these complex constructs are not necessary to recover, organize and predict the observed structure.

The work therefore cannot be fairly evaluated if theoretical interpretation is treated in advance as the evidentiary ground truth and an empirical structure is dismissed as “curve fitting” merely because it does not begin from the familiar theoretical ontology.

A recently completed companion paper [link] demonstrates that the spectral framework achieves the rare capability of metaprediction: it predicts both the empirical spectral values of atomic properties and the values produced by competing theoretical relativistic and quantum calculations without using these theories, and explains where and why both predictions diverge. This provides a concrete empirical reason to be cautious about granting explanatory priority to a theoretical account when the relevant structure can already be recovered and quantitatively predicted from measured spectral relations alone without invoking complex theoretical machinery.

I recognize that this is a transdisciplinary body of work asking unusual foundational scientific questions, and that identifying appropriate expertise may be difficult. The central claim is that a highly compressed empirical structure in the frequency domain underlies atomic systems and permits organization, explanation, and quantitative prediction directly from only two measured spectral coordinates, prior to the introduction of atomic number, atomic models and their theoretical machinery. The claims are substantial, but so is the empirical evidence offered in support of them.

To make independent evaluation as direct and efficient as possible, the papers contain all datasets and information needed for full reproducibility. In addition, the interactive PNAS review record contains the complete point-by-point rebuttal and the relevant evidence associated with each claim. We have also built the interactive Spectral Map of the Elements to visualize and interrogate the full dataset, relationships, and results presented in Paper 3, and built the interactive Predictive Engine of Atomic Properties to visualize and evaluate the relationships and predictive power of Papers 1 and 2 beyond the examples provided in the papers, and beyond what current theoretical models can achieve.

Because this is a purely empirical framework using basic mathematics, and free of abstract constructs and complex formalism, the analysis can be checked directly against the data with minimal interpretive or computational effort. The simplicity of the empirical spectral laws unveiled in this package is itself a result. Therefore, if the package is difficult to assimilate, the difficulty does not arise from mathematical complexity or style, but from the fact that it challenges the hierarchy between measurement and theory that has governed atomic physics and chemistry for roughly a century. If independently reproduced, this would mean that a much lower-dimensional empirical structure sits underneath phenomena currently partitioned among many separate theoretical mechanisms. This is why the package warrants consideration at PNAS.

I would also welcome the opportunity for a direct scientific audit of the complete body of work. I am prepared to present the full evidentiary structure to a small group of appropriately selected scientists and editors and to answer, in real time, any mathematical, empirical, or conceptual questions concerning the studies. This would not replace independent peer review, but would provide an additional opportunity to interrogate the evidence, reproduce the central calculations, test the principal claims, and resolve conceptual misunderstandings that may be difficult to address through isolated manuscript reviews.

I respectfully ask the Editors to read this letter in full and examine the linked review record. I recognize the significance of the claims being made, and I believe claims of this scope warrant correspondingly careful scrutiny of the evidence.

My request is that the empirical claims be evaluated directly, under the same standards of reproducibility, compression, quantitative prediction, falsifiability, generalizability, and distinguishability of competing explanations that would apply to any proposed physical framework, and that the coordinated body of evidence be subjected to an independent technical assessment on those grounds, rather than resolved through epistemological judgments about the hierarchy between theory and measurement, an issue we address separately in other non-technical work [link].

The central question raised by this work, and one that warrants consideration by editors and reviewers, is this: how can a simple two-coordinate system in frequency space, with no theoretical input, recover atomic and periodic organization with substantial compression and precision; unify phenomena such as fine structure and periodic recurrence that are conventionally treated as independent; predict both empirical spectral values and theoretical relativistic and quantum calculations, including their divergence, without using those theories as inputs; and generate explicit, falsifiable predictions across systems, achievements that ordinarily require complex and diverse theoretical machinery and extensive computation?

Equally important, why does this simple relational organization emerge only when atomic number Z, an external ordinal index, is replaced by a metric spectral coordinate intrinsic to the system?

If any statement in the public record misrepresents an editorial or reviewer comment, or if any empirical or mathematical claim in our response is demonstrably incorrect, I welcome a specific correction and will amend the record accordingly.

Sincerely,
Abdennour Abbas
abbas@spectralframework.org

COMPLETE RECORD

Documents, decisions, reports, and supporting material

The original submission record and subsequent papers are separated below. Subsequent papers were not included in the submitted PNAS package.

PNAS submission record

Subsequent papers not included in the package

Technical papers

Epistemological and methodological papers

Public-record standard. If an editorial or referee statement is represented inaccurately here, or if an empirical or mathematical response is demonstrably incorrect, the record should be amended with the specific correction and supporting evidence. Correspondence should be addressed to: abbas@spectralframework.org
Reviewer report