Rotational Spectroscopy of <i>p</i>-Toluic Acid and Its 1:1 Complex with Water
Bibliographic record
Abstract
The structure and internal dynamics of p -toluic acid and its 1:1 complex with water were investigated in the gas phase using chirped-pulse and cavity-based Fourier transform microwave spectroscopy. One conformer and one isomer were identified for the monomer and monohydrate, respectively. In the monohydrate, water acts as both a hydrogen bond donor and acceptor, participating in a six-membered intermolecular ring with the carboxyl group. Both a - and b -type transitions were observed for the monomer; only a -type transitions were observed for the monohydrate. Rotational transitions of both species show splittings originating from methyl internal rotation, for which the potentials include 3- and 6-fold symmetry terms of similar amplitude. For the monomer, a few b -type transitions are missing, and their intensities were found to be transferred to c -type transitions with common energy levels, which are otherwise forbidden. No splittings attributable to a water internal tunneling motion were observed for the monohydrate. Furthermore, the absence of c -type transitions in the spectrum of the monohydrate, despite the large μ c dipole moment component of the equilibrium geometry obtained by ab initio calculations, is consistent with a barrierless wagging motion of the free hydrogen of water, leading to an average μ c dipole moment component of zero. These results provide insights regarding the interactions between atmospheric p -toluic acid and water in prenucleation complexes and at the air–water interface of aqueous aerosols, where p -toluic acid may act as a surfactant.
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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 | 0.000 | 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) | 0.001 | 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".