Vibrational Overtone Spectroscopy and Overtone Intensities of Cyclohexadiene Iron Tricarbonyl and 1,3-Cyclohexadiene
Bibliographic record
Abstract
The CH stretching overtone spectra of liquid cyclohexadiene iron tricarbonyl (CHDIT) have been recorded for the first, second, and third overtone regions (Δ v = 2−4). The gaseous spectrum of CHDIT has also been obtained for the first overtone region (Δ v = 2). Observed transitions are assigned to the overtones of different nonequivalent CH bonds and to the local mode−normal mode combination bands. Oscillator strengths have been calculated with the harmonically coupled anharmonic oscillator (HCAO) local mode model and ab initio dipole moment functions. The theoretical values have been compared to the experimental oscillator strengths and agree well with experiment. The comparison of the overtone spectrum of CHDIT to the corresponding spectrum of uncomplexed 1,3-cyclohexadiene reveal changes that occur in the ligand upon complexation with iron tricarbonyl. The presence of the metal lengthens the terminal olefinic CH bond by 0.002 Å and shortens the nonterminal olefinic CH by 0.001 Å. The axial and equatorial CH bonds of the free ligand become similar in length in the complex. The implications of the observed spectral features to the structure and bonding in the complex are discussed.
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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 | 0.000 | 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) | 0.004 | 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".