The isotope effect and orientational potentials of methane molecules in gas hydrates
Bibliographic record
Abstract
We report an inelastic neutron scattering experiment at T=2 K of a fully deuterated methane hydrate CD4⋅5.75 D2O. In the experiment the J=0→J=1 rotational transition of an almost free quantum CD4 rotor at an energy transfer of 0.4 meV has been found. No line splitting due to the two different kinds of cages, which are occupied by the methane molecules in the host lattice, has been found. Using a simple electrostatic model of the orientational interaction between the methane molecules and the water molecules in the host lattice we are able to explain the measured spectra of both the deuterated and protonated samples. The intrinsic linewidth found for the rotational transition in deuterated and protonated samples can be attributed to the frozen in disorder of the water dipole moments in the cages. The contribution of the van der Waals interaction has also been calculated on the basis of empirical atom–atom interaction parameters and has been found to be one order of magnitude smaller than the electrostatic interaction. In addition the calculated orientational scattering length density of the CD4 molecules is found to be in good agreement with experimental values. It is shown, that previous diffraction experiments lead to only limited information about the orientational distribution function due to the proton disorder.
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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 | 0.001 |
| 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 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".