Dimers and trimers of HF, H<sub>2</sub>O, NH<sub>3</sub> and CH<sub>4</sub> with N<sub>2</sub>. Ab initio studies on structures and vibrational frequencies
Bibliographic record
Abstract
High level ab initio calculations have been performed on the trimers of HF, H2O, NH3 and CH4 (XHn) with N2 using the Møller-Plesset MP2 method, as well as on respective dimers, using both coupled cluster CCSD(T) and MP2 methods. Guided by structure and stability of the dimers, various structures of trimers were investigated. Dissociation energies De are highest for the 2;1 trimers (XHn)2-N2, and smaller for the 1:2 trimers XHn-(N2)2. For dimers and trimers dissociation energies decrease in going from HF to CH4. For HF to NH3, dissociation energies of the (XHn)2-N2 trimers lie 100–300 cm−1 above the sum of respective dimer values. Harmonic vibrational frequencies and infrared intensities were calculated using the MP2 method. Frequency shifts are largest for the (XHn)2-N2 complexes. They are negative (red shifted) for stretching modes, and positive (blue shifted) for the bending modes. They decrease in going from HF to CH4. Infrared intensities for the complexes are usually much enhanced over the monomer values. This applies especially to vibrations corresponding to symmetric stretching modes of (XHn)2 and (XHn)2-N2 complexes for H2O and NH3. Intensities of intermolecular vibrational modes exceed in many cases the intensities of fundamental modes of the monomers.
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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) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 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".