Extending 17O transverse relaxation measurement to satellite transitions as a direct probe of molecular dynamics in solids
Bibliographic record
Abstract
We report utilization of transverse relaxation rate ( R 2 ) of 17 O ( I = 5/2) satellite transitions (STs) as a probe of molecular dynamics in solids. A simple theoretical model using spectral density functions is proposed to describe the general R 2 behaviors of half-integer quadrupolar nuclei in solids in the presence of molecular motion (or chemical exchange). Experimental 17 O R 2 data recorded for both CT and ST from 17 O-labeled NaNO 2 over a large temperature range are used to verify the theoretical predictions. Our theoretical model is shown to be fully consistent with a full quantum mechanical treatment of the chemical exchange problem involving half-integer quadrupolar nuclei in solids by numerically solving the Liouville-von Neumann equation. The new 17 O ST R 2 method was also applied to study the carboxylate flipping motion in two [ 17 O]carboxylic acid-pyridine adducts in the solid state. The advantages of the ST R 2 approach are discussed. This ST R 2 approach adds a new dimension to the currently available CT-based solid-state NMR techniques for probing molecular motion in solids. • Transverse relaxation from 17 O satellite transitions was used to probe molecular motion in solids. • A theoretical model is proposed to describe transverse relaxation times for both central and satellite transitions. • Molecular motions were examined in both ionic solids and organic solids containing strong hydrogen-bonds.
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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".