Chromophore Analysis of Near-Edge X-ray Absorption Spectra: Application to Four-Coordinate Phosphorus
Bibliographic record
Abstract
This paper reports X-ray chromophore behavior: the substituents of an X-ray-absorbing atom (here phosphorus) were found to contribute consistent absorptions, in intensity and in relative peak position (transition energy). Linear relations for absolute peak position, as a function of the sum of the phosphorus neighbor-atom electronegativities (Σχ), have been found for ten chromophore peaks: P–F, P–O, P–Cl, P–N, P–C I, P–W I, P–C II (Ph), P–C II (pyr) P–C II (Fc), P–W II . The discovery was made by finding (i) surprisingly rich phosphorus K-edge X-ray absorption spectra [P X-ray absorption spectroscopy (XAS)] for several four-coordinate-phosphorus compounds, including four new ones involving the W(CO) 5 substituent, (ii) a vastly improved time-dependent (linear-response-based) density-functional-theory prediction method for P XAS which provides unprecedented XAS peak-assignment ability, and (iii) a fresh antibonding-orbital-based interpretive framework. The discovery, that selective X-ray excitation of substituents is possible, opens the door for studies of chemical reactivity implications (X-ray photochemistry), and improved studies of X-ray radiation exposure effects and damage.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".