Absolute intensities of Raman trace scattering from bicyclo-[1.1.1]-pentane
Bibliographic record
Abstract
Our previous theoretical studies have identified the Raman intensity parameter for the bridgehead C-H stretch in bicyclo-[1.1.1]-pentane as the largest for any saturated hydrocarbon yet considered, while the methylene C-H parameter is predicted to be ordinary. Theoretical methods including self-consistent field, static and time dependent density functional theory, and coupled cluster, all predict a large bridgehead intensity parameter, but differ widely in the actual value. We have synthesized bicyclo-[1.1.1]-pentane and recorded the absolute intensity Raman trace scattering spectra. The recorded intensity of a resonance polyad in the C-H stretching region has been resolved and distributed onto the fundamental modes through an anharmonic resonance analysis from a computed quartic force field. The experimental internal coordinate intensity parameters have been obtained and compared with those computed. Although the static and dynamic density functional values overestimate the parameter by 10%-18%, the values predicted at the coupled-cluster level are found to be correct to within experimental error.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| 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) | 0.003 | 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".