Rotational study of carbon monoxide isotopologues in small 4He clusters
Bibliographic record
Abstract
High resolution microwave (a-type) and millimetre-wave (b-type) spectra of HeN–13C16O, HeN–12C18O, and HeN–13C18O clusters (N ≤ 10) were observed, significantly extending the initial spectroscopic observations on HeN–12C16O by Surin et al. [Phys. Rev. Lett., 2008, 101, 233401]. The frequencies of the a-type series, which evolves from the end-over-end rotation of the dimer, decrease from N = 1 to 3, then increase smoothly to at least N = 9. This turnaround indicates a rapid evolution of the solvation character from classical to quantum. The b-type series, which evolves from the free molecule rotation of CO, increases from N = 0 to 6 and then decreases to at least N = 10. This is consistent with an initially increasing anisotropy of the helium environment, followed by a tendency of the solvation shell to become more isotropic. The shift of the vibrational frequency of CO as determined from the infrared [A. R. W. McKellar, J. Chem. Phys., 2004, 121, 6868; ibid., 2006, 125, 164328] and microwave data reveals an approximately linear decrease from N = 1 to at least 9. If the linear shift were to continue until completion of the first solvation shell (N ≈ 14), the estimated helium nanodroplet shift will be well undershot [K. von Haeften, S. Rudolph, I. Simanovski, M. Havenith, R. E. Zillich and K. B. Whaley, Phys. Rev. B: Condens. Matter Mater. Phys., 2006, 73, 054502]. In this case, there must be an upturn in the vibrational shift beyond N = 14, which is not predicted by theory [T. Škrbić, S. Moroni and S. Baroni, J. Phys. Chem. A, 2007, 111, 7640]. By extrapolating the a-type series to N = 14 (assuming a linear vibrational shift), we estimate the rotational constant, B, of CO in the helium nanodroplet to be ∼74% of its gas phase value. This is in reasonable agreement with simulations (76% at N = 14), which predict the limiting value to be approximately reached upon completion of the first solvation shell (73% at N = 100) [T. Škrbić, S. Moroni and S. Baroni, J. Phys. Chem. A, 2007, 111, 7640]. However, this value is significantly larger than that inferred from helium nanodroplet experiments (63%).
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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) | 0.001 | 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".