CH-Stretching Overtone Spectra of 3-Hexyne and Butane
Bibliographic record
Abstract
We have recorded vapor-phase CH-stretching overtone spectra of 3-hexyne in the Δ v CH = 2−8 regions and of 3-hexyne- d 10 in the Δ v CD = 2−7 regions. We have recorded CH-stretching overtone spectra of butane in the Δ v CH = 2−7 regions and of propane in the Δ v CH = 7 and 8 regions to facilitate comparison with the 3-hexyne spectra. The spectra were recorded at room temperature with the use of conventional and intracavity laser photoacoustic spectroscopy. The spectra can be explained in terms of a harmonically coupled local-mode model (HCAO) with one oscillator for each of the nonequivalent CH bonds. Spectral assignments are made and correlated with ab initio geometry optimized structures. The intensities of the CH stretching transitions are calculated using the HCAO local-mode model and ab initio dipole moment functions. Parameters for the calculations come from a local-mode analysis of the spectra and from ab initio calculations. Our simple calculations are in good agreement with the observed absolute and relative intensities. The ethyl group in 3-hexyne is freely rotating, but there is little difference in the CH bond length with the ethyl group position. No peaks due to internal methyl or ethyl rotation are observed in the spectra of 3-hexyne. The frequency of the in-plane methyl bond increases significantly in 3-hexyne compared to those in propane and butane.
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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".