The simulation of X-ray absorption spectra including vibronic coupling: application of the QD-DFT/MRCI(2) method
Bibliographic record
Abstract
the construction of vibronic coupling Hamiltonians, including anharmonicity through 6th-order in the one-mode terms, as well as bilinear two-mode coupling terms. The models include all vibronically-coupled core-excited states below the core-ionization potential: 24, 27, and 26 states of the C K-edge for ethylene, allene, and butadiene, respectively. These results, which furnish excellent agreement with recently measured X-ray absorption spectra, demonstrate the effectiveness of the QD-DFT/MRCI(2) method. Further, they highlight the importance of accounting for vibronic coupling in first principles simulation of X-ray absorption spectra. Specifically, we demonstrate that simulations constructed from best estimate vertical excitation energies and oscillator strengths alone generally fail to predict the positions of experimental peak maxima, particularly for transition energies above the band origin.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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 source (direct Gemma or distilled Codex), 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".