Linear and bent triatomic molecules are <i>not</i> qualitatively different!
Bibliographic record
Abstract
I, and other authors, have discussed in several recent publications that “linear” triatomic molecules (defined as having linear equilibrium structures) are necessarily observed as being bent on ro-vibrational average. We have demonstrated this theoretically by calculations of the rotation–vibration expectation values, [Formula: see text], where [Formula: see text] is the bond angle supplement, [Formula: see text] being the instantaneous value of the bond angle of the triatomic molecule A–B–C. Direct experimental evidence of bent average structures has been obtained by other authors in Coulomb explosion imaging experiments, and indirect evidence from re-interpretation of experimentally derived rotational constant values. In spite of a rather significant amount of evidence in support of the bent average structures, the idea has been heavily criticized. In the present work I discuss in more detail some of the arguments for the bent average structures put forward in previous papers, and I hope to correct and clarify some of the misunderstandings leading to the criticisms. Part of the criticism originates in a widespread, but fallacious, belief among spectroscopists that linear and bent chain molecules have qualitatively different energy-level and spectral intensity patterns. This is not true. One can view the linear-molecule energy level and spectral patterns as limiting cases of the bent-molecule ones.
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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 | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.005 |
| Scholarly communication | 0.002 | 0.004 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.005 | 0.001 |
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".