Phosphorus-31 and vanadium-51 solid-state nuclear magnetic resonance spectroscopy of β-vanadyl phosphate — Effects of homo- and heteronuclear spin-spin, electrostatic, and paramagnetic interactions
Bibliographic record
Abstract
Field-dependent 31 P solid-state NMR studies demonstrate that the line shape in spectra of β-VOPO 4 depends on 51 V– 31 P direct and indirect spin-spin interactions (M 2 ( 51 V, 31 P) = 101(23) × 10 6 rad 2 s –2 , 2 J iso ( 51 V, 31 P) = 48(5) Hz) and, to a lesser extent, on 31 P chemical shift anisotropy (δ iso = –10.4(2), Ω = δ 11 – δ 33 = 22(2) ppm) and 31 P– 31 P interactions (M 2 ( 31 P, 31 P) = 6.7(1) × 10 6 rad 2 s –2 ). In contrast, homonuclear dipolar interactions play an important role for the field and spinning rate dependent 31 P spin-lattice relaxation via paramagnetic impurities (T 1 = 20–60 s). Vanadium-51 magic-angle spinning NMR spectra indicate a sizeable chemical shift anisotropy (δ iso = –754(1), δ 11 = –336(10), δ 22 = –344(6), δ 33 = –1581(8) ppm) and nuclear quadrupole interaction (χ = 1.5(1) MHz, η = 0.35(5)); the principal axis systems of both interactions are clearly not coincident, with an angle of 35(5)° between the greatest component of the electric field gradient tensor and δ 33 .
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 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 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".