The vibration-rotation emission spectrum of hot BeF2
Bibliographic record
Abstract
The high-resolution infrared emission spectrum of BeF2 vapor at 1000 degrees C was rotationally analyzed with the assistance of large-scale ab initio calculations using the coupled-cluster method including single and double excitations and perturbative inclusion of triple excitations, in conjunction with correlation-consistent basis sets up to quintuple-zeta quality. The nu3 fundamental band, the nu1+nu2, nu1+nu3, and 2nu2+nu3 combination bands, and 18 hot bands were assigned. The symmetric stretching (nu1), bending (nu2), and antisymmetric stretching (nu3) mode frequencies were determined to be 769.0943(2), 342.6145(3), and 1555.0480(1) cm-1, respectively, from the band origins of the nu3, nu1+nu3, and nu1+nu2 bands. The observed vibrational term values and B rotational constants were fitted simultaneously to an effective Hamiltonian model with Fermi resonance taken into account, and deperturbed equilibrium vibrational and rotational constants were obtained for BeF2. The equilibrium rotational constant (Be) was determined to be 0.235 354(41) cm-1, and the associated equilibrium bond distance (re) is 1.3730(1) A. The results of our ab initio calculations are in remarkably good agreement with those of our experiment, and the calculated value was 1.374 A for the equilibrium bond distance (re). As in the isoelectronic CO2 molecule, the Fermi resonance in BeF2 is very strong, and the interaction constant k122 was found to be 90.20(4) cm-1.
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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".