Chiroptical properties from time-dependent density functional theory. I. Circular dichroism spectra of organic molecules
Bibliographic record
Abstract
We report the implementation of the computation of rotatory strengths, based on time-dependent density functional theory, within the Amsterdam Density Functional program. The code is applied to the simulation of circular dichroism spectra of small and moderately sized organic molecules, such as oxiranes, aziridines, cyclohexanone derivatives, and helicenes. Results agree favorably with experimental data, and with theoretical results for molecules that have been previously investigated by other authors. The efficient algorithms allow for the simulation of CD spectra of rather large molecules at a reasonable accuracy based on first-principles theory. The choice of the Kohn–Sham potential is a critical issue. It is found that standard gradient corrected functionals often yield the correct shape of the spectrum, but the computed excitation energies are systematically underestimated for the samples being studied. The recently developed exchange-correlation potentials “GRAC” and “SAOP” often yield much better agreement here with experiments for the excitation energies. The rotatory strengths of individual transitions are usually improved by these potentials as well.
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.004 | 0.001 |
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".