Density Functional Study of Absorption and Resonance Raman Spectra of Pyromellitic Diahydride (PMDA) Anion
Bibliographic record
Abstract
The electronic structure of the low-energy states of pyromellitic diahydride (PMDA) anion is investigated in terms of density functional theory (DFT). The studies are carried out with a use of the local spin density VWN (Vosco−Wilk−Nusair) and the nonlocal spin density BP (Becke−Perdew) models. To explore the role of the diffuse functions located on carbon and oxygene atoms, the B3LYP method was also employed with 6-31+G* and 6-31G* basis sets. At this level of approximation, the Franck−Condon (FC) parameters were evaluated for the nine totally symmetric modes of PMDA anion in its low-energy dipole-allowed 1 2 B 3g and 1 2 B 1g states. These parameters are then employed to reconstruct and discuss the vibrational structure of the experimental absorption and RR spectra measured in the region corresponding to the low-energy 1 2 A u → 1 2 B 3g transition. It is shown that a weak mixing of the CC stretching modes upon excitation to the 1 2 B 3g state and an inhomogeneous broadening of vibronic transitions have a marked effect on the absorption and resonance Raman spectra.
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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 | 0.000 |
| 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".