Absolute Intensities of CH Stretching Overtones in Alkenes
Bibliographic record
Abstract
We have measured the CH stretching vibrational spectrum of ethene gas in the regions corresponding to 1-5 quanta in the CH stretching vibration with Fourier transform infrared and conventional absorption spectroscopy and have determined the corresponding oscillator strengths. We have calculated the CH stretching vibrational oscillator strengths for a series of alkenes: ethene, propene, 1,3-butadiene, cis-2-butene, and trans-2-butene. The CH stretching intensities are calculated with a simple Morse oscillator local mode model for CH groups and with the harmonically coupled anharmonic oscillator local mode model for CH2 and CH3 groups. The local mode parameters, frequencies, and anharmonicities are obtained from experiments. The harmonic coupling coefficients and the dipole moment functions are calculated with a range of ab initio methods. These include self-consistent-field Hartree-Fock, density functional, correlated, and multireference theories, combined with basis sets ranging from double- to quadruple-zeta quality augmented with polarization and diffuse functions. Variation in calculated oscillator strengths with the choice of ab initio method is systematically studied and compared with observed intensities. From this comparison between the calculated and observed values, we can quantitatively understand the relative usefulness of various ab initio dipole moment functions in calculations of vibrational oscillator strength for alkenes.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| 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".