Isotopic Identification of Quadrupolar Spin Resonance Lines by Zeeman Perturbation
Bibliographic record
Abstract
Quadrupolar spin resonance (QSR) is radio frequency spectroscopy that provides a chemical fingerprint in the absence of a magnetic field. Materials may present QSR spectra featuring multiple overlapping isotopic resonances, leading to ambiguous spectral assignments. We show how the application of a weak magnetic field (≤50 mT) enables measurement of the nuclear gyromagnetic ratio associated with each resonance with sufficient precision for isotopic identification. The method is demonstrated on pure and impure powdered samples, and the concept of multisite multinuclear QSR spectral fitting is introduced. New insights are thereby gained into the sensitivity of the Zeeman-QSR response and the characterization of complex samples. This approach creates new opportunities in QSR spectroscopy and provides a sustainable cryogen-free alternative to helium-cooled superconducting magnets associated with high-field NMR.
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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 | 0.001 |
| 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".