Ab initio studies of the vibrational spectra of some hydrogen-bonded complexes of fluoroacetylene
Bibliographic record
Abstract
Ab initio molecular orbital theory has been used to compute the properties of a number of hydrogen-bonded complexes between fluoroacetylene as proton donor and ammonia, water, hydrogen fluoride, phosphine, hydrogen sulfide, and hydrogen chloride as proton acceptors. The properties considered were the vibrational spectra, the molecular structures, the hydrogen-bond energies, and the electron densities, and one of the aims of the study was to ascertain whether there was any evidence of blue-shifting hydrogen-bond character in the complexes formed. The adducts with NH 3 , H 2 O, PH 3 , and H 2 S were of the conventional CH···X kind (X = N, O, P, S), with hydrogen-bond energies decreasing in the order NH 3 > H 2 O > PH 3 ≈ H 2 S. Those formed with HF and HCl showed the presence of three alternative structures; in addition to the CH···F(Cl) complexes, adducts of the F(Cl)H···F and F(Cl)H···π type were also found to be stationary points on the potential energy surfaces, with stabilities in the order F(Cl)H···π > CH···F(Cl) > F(Cl)H···F. The hydrogen-bond energies of the CH···X series correlated with the gas-phase basicities of the proton acceptors; moreover, the CH bond-length changes, the wavenumber shifts, the complex–monomer infrared intensity ratios of the CH stretching modes, and the amounts of charge transferred on complex formation were all found to track with the hydrogen-bond energies. All those properties considered here are consistent with the formation of red-shifting hydrogen bonds, to the exclusion of the blue-shifting alternatives.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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 | 0.001 |
| 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 teacher head, 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".