Computing Rovibrational Spectra of Small Polyatomic Molecules with Variational and Collocation Methods
Bibliographic record
Abstract
It is well-known that some deuterated isotopologues of interstellar molecules achieve a significantly higher deuterium-to-hydrogen ratio than the natural elemental abundance. CH3+ and its deuterated isotopologues are thought to be an important mediator of this process in warm interstellar regions and as such their detection is of interest. To assist in experimental observation, rovibrational calculations have been performed for all isotopologues of CH3+ up to J = 5. Rovibrational levels of CH2D+ and CD2H+ are computed for the first time. Vibrational states up to the 5000-6000 cm-1 range are assigned and their symmetry is determined. The J < 6 levels for the ground, ν1, and ν5 states of CH2D+, and the ground state of CD2H+ compared to observed levels all have a root-mean-square-error (rmse) of less than 0.1 cm-1. The rmse increases to over 0.5 cm-1 for the ν1 mode of CD2H+, thought to be due to a perturbation with another band. Though prior analysis proposes the ν2 +ν 3 overtone as most likely for a perturbing Fermi resonance, these calculations suggest 3ν 3 as the more probable candidate. In addition, the progress on an additional project aimed at supplementing sum-of- products routines is outlined. Preliminary results for P2O look promising, and calculations are presently moving forward on a CH2O example to test the proposed idea.
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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 | 0.004 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| 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".