CO2 DIMER: FOUR INTERMOLECULAR MODES OBSERVED VIA INFRARED COMBINATION BANDS
Bibliographic record
Abstract
Study of the carbon dioxide dimer has a long history, but there is only one previous observation of an intermolecular vibration [1]. Here we analyze four new combination bands of (CO$_{2}$)$_{2}$ in the CO$_{2}$ \\nub{3} region ($\\sim$2350 \\wn), observed using tunable infrared lasers and a pulsed slit-jet supersonic expansion. The previous combination band at 2382.2 \\wn was simple to assign [1]. A much more complicated band ($\\sim$2370 \\wn) turns out to involve $two$ upper states, one at 2369.0 \\wn ($B_{u}$ symmetry), and the other at 2370.0 \\wn ($A_{u}$). The spectrum can be nicely fit by including the Coriolis interactions between these states. Another complicated band around 2443 \\wn also involves two nearby upper states which are highly perturbed in so-far unexplained ways (possibly related to tunneling shifts).\n \nWith the help of new $ab$ $initio$ calculations [2], we assign the results as follows. The 2369.0 \\wn band is the combination of the forbidden $A_{g}$ intramolecular fundamental (probably [1] at about 2346.76 \\wn) and the intermolecular geared bend ($B_{u}$). The 2370.0 \\wn band is the combination of the same $A_{g}$ fundamental and the intermolecular torsion ($A_{u}$). This gives about 22.3 and 23.2 \\wn for the geared bend and torsion. The previous 2382.2 \\wn band [1] is the allowed $B_{u}$ fundamental (2350.771 \\wn) plus two quanta of the geared bend ($B_{u}$), giving 31.509 \\wn for this overtone. The highly perturbed 2442.7 \\wn band is the $B_{u}$ fundamental plus the antigeared bend ($A_{g}$), giving about 91.9 \\wn for the antigeared bend. Finally, the perturbed 2442.1 \\wn band is due to an unknown combination of modes which gains intensity from the antigeared bend by a Fermi-type interaction. Calculated values [2] are: 20.64 (geared bend), 24.44 (torsion), 32.34 (geared bend overtone), and 92.30 \\wn (antigeared bend), in good agreement with experiment. \n\\vskip 0.2 truecm \n[1] M. Dehghany, A.R.W. McKellar, Mahin Afshari, and N. Moazzen-Ahmadi, \\textit{Mol. Phys.} \\textbf{108}, 2195 (2010). \n \n \n[2] X.-G. Wang, T. Carrington, Jr., and R. Dawes, private communication.
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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 | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| 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".