The measurement of residual dipolar coupling between quadrupolar nuclei in double-rotation NMR
Bibliographic record
Abstract
Measuring internuclear distances using dipolar coupling constants (RDD) is a particular challenge in the case of heteronuclear quadrupolar spin pairs. When the quadrupolar interaction is too large, the entire spectrum cannot be excited in a single piece and double resonance methods cannot be used. A second possibility is to use residual dipolar coupling (RDC) to extract RDD as RDCs are amplified when the quadrupolar interaction increases. RDCs are often seen in the magic angle spinning (MAS) NMR spectra of spin-1/2 nuclei that are dipolar coupled to a quadrupolar nucleus although they are more elusive in the case of quadrupolar spin pairs because the quadrupolar interaction typically dwarves all other interactions. In order to resolve these RDCs and measure RDDs it is advantageous to remove the second-order quadrupolar broadening using a high-resolution method such as doublerotation (DOR).
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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 | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.001 |
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".