Microwave Spectra, Geometries, and Hyperfine Constants of OCCuX (X = F, Cl, Br)
Bibliographic record
Abstract
A pulsed jet cavity Fourier transform microwave spectrometer has been used to measure the rotational spectra of OCCuX (X = F, Cl, Br) in the frequency range 5-21 GHz. Metal atoms were generated via laser ablation and were allowed to react with CO and a halide precursor, prior to stabilization of the products within a supersonic jet. These are the first experimental observations of OCCuF and OCCuBr and the first high-resolution spectroscopic study of gas-phase OCCuCl. All three molecules were found to be linear. Rotational constants, centrifugal distortion constants, nuclear quadrupole coupling constants, and nuclear spin-rotation coupling constants have been precisely determined. The rotational constants have been used to evaluate the various bond lengths, and the results are in good agreement with the trend established for OCAuX species. The C-O distance is found to be comparatively short and close to that of free CO. The M-C distance is longer than that predicted by ab initio calculations, and the Cu-X distances are very similar to those observed in the corresponding metal halides. Vibrational wavenumbers have been estimated from the distortion constants and are compared with the results of various ab initio studies. Changes in the Cu, Cl, and Br nuclear quadrupole coupling constants indicate that substantial charge rearrangement takes place on coordination with CO, consistent with the formation of strong Cu-C bonds. Mulliken orbital population analyses have been performed and provide evidence of pi-back-donation from Cu in all of the species studied. The evaluated nuclear spin-rotation coupling constants have been used to estimate the (63)Cu nuclear shielding constants, sigma, and their spans (Omega) in OC(63)CuF, OC(63)Cu(35)Cl, and OC(63)Cu(79)Br.
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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 | 0.000 |
| 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".