Signatures of rotation–translation couplings, symmetry-breaking, and intermolecular interactions in the rovibrational spectra of solid H2O@C60
Bibliographic record
Abstract
Some spectral features observed in the rovibrational spectra of solid H2O@C60 are shown to provide spectroscopic signatures of confinement-induced perturbations related to the coupling between the orientational and positional degrees-of-freedom of the water molecules. Their attribution to either para-H2O@C60 or ortho-H2O@C60 is established from their behavior during nuclear spin conversion. The frequency of the rovibrational transitions that emanate from their ground ro-translational (RT) states appears conspicuously redshifted from that of the corresponding transitions in the free water molecule in the gas phase. However, a few of the 21 hot band spectral features, and one ground state transition, observed in the infrared spectrum of solid H2O@C60 and reported here for the first time, cannot be straightforwardly assigned based on the softening of its intramolecular HOH bending and OH stretching vibrational modes due to confinement within C60. The most strongly perturbed transitions provide insights into the complex confinement-induced quantum nuclear dynamics arising from rotation-translation coupling, allowing the topology of the confinement potential to be revealed using a simple confined rotor model [Putaud et al., J. Chem. Phys. 162, 144313 (2025)]. While the line profiles exhibited by most of the transitions are consistent with symmetry-breaking interactions arising from merohedral disorder in solid H2O@C60, evidence for additional perturbations of the 10100 RT state, in the ground and vibrationally excited manifolds, is reported. Moreover, the line profiles displayed by the transitions emanating from the ground RT state of para-H2O@C60 and the observation of nominally forbidden Q-branch transitions, in the intramolecular HOH bending and symmetric OH stretching ranges of solid H2O@C60 samples with a fill ratio of 75%, are shown to provide a spectroscopic signature of intermolecular dipolar interactions between nearest-neighbor H2O@C60 molecules.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 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".