Rovibronic transitions between the A <sup>2</sup> Σ <sup>+</sup> and B <sup>2</sup> Σ <sup>+</sup> states of the OH radical
Bibliographic record
Abstract
The spectrum of the hydroxyl radical OH plays a crucial role in diverse environments, including planetary atmospheres, astrophysical media, and combustion processes. Accurate modeling of its spectral signatures requires reliable descriptions of rovibronic transitions. In this work, we present a new high-resolution spectroscopic study of the B 2 Σ + −A 2 Σ + band system of the OH radical. Transition dipole moment functions (TDMFs) were computed using the multireference configuration interaction method with Davidson correction (MRCI + Q) and the aug-cc-pV5Z basis set. These TDMFs, along with the potential energy curves from literature, were employed in LeRoy's LEVEL program to generate transition dipole moment matrix elements (TDMMEs). The TDMMEs were then transformed to Hund's case (a) to account for electron spin effects. The resulting dataset provides a fully resolved set of rovibronic transitions, including line position, line strength, Einstein A coefficients, and the detailed quantum numbers ( e/ f parity, F 1 / F 2 , v, J, N). To our knowledge, this represents the first systematic spectroscopic model for the B 2 Σ + −A 2 Σ + system computed using post-Hartree–Fock methods and a quintuple-zeta basis. Importantly, it incorporates all rovibronic transitions within this band system, including weak lines often neglected in previous studies. This work is the most complete and accurate resource to date for modeling the B 2 Σ + −A 2 Σ + band system of OH.
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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 | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| 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".