Isotopic probing of weak intermolecular forces: Infrared spectrum and energy levels of the C13O16 dimer
Bibliographic record
Abstract
The infrared spectrum of the fully substituted 13-C carbon monoxide dimer, (13C16O)2, has been studied in the region of the C–O stretching vibration, around 2096 cm−1. Over 120 transitions have been assigned to transitions involving 49 rotational levels in the excited state and 23 levels in the ground state. Relative energies for all these levels have been accurately (≈0.0003 cm−1) determined without model dependence, except for the interval between the lowest levels of A and B symmetry. The observed stacks of levels were similar to those determined previously for the normal isotope, (12C16O)2, and could therefore be identified with the same labeling scheme, but the differences between them constitute a subtle probe of the intermolecular forces in this system. In both isotopes, the stacks fall into two groups, characterized by larger (4.4 Å) or smaller (4.0 Å) intermolecular separations. The energy splitting between the ground states of these two isomers is 0.877 cm−1 in (12C16O)2, and 1.285 cm−1 in (13C16O)2. The observed isotope shifts may be explained in terms of a simple anharmonic interaction model.
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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) | 0.002 | 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".