<sup>73</sup>Ge Solid-State NMR of Germanium Oxide Materials: Experimental and Theoretical Studies
Bibliographic record
Abstract
A comprehensive series of crystalline germanates has been studied by ultrahigh-field 73 Ge NMR and quantum chemical calculations. Despite its low gyromagnetic ratio, low natural abundance and large quadrupole moment, interpretable spectra were obtained in almost all cases, demonstrating that 73 Ge is an accessible NMR nucleus. The spectra yield a wide range of quadrupole coupling constants ( C Q = 9 to 35 MHz), with calculations indicating a range twice that, which are rationalized principally in terms of the variation in Ge−O bond lengths. The isotropic chemical shifts appear to fall into distinct regions for four-, five-, and six-coordinate Ge, with increasing coordination number corresponding to lower frequencies. Both CASTEP and WIEN2k consistently underestimate the C Q s, suggesting that the exchange-correlation functional is poorly optimized for these systems. 73 Ge NMR spectra of alkali germanate glasses are broad and featureless, rendering them difficult to interpret in terms of specific structural elements, even with the well understood NMR parameters from the crystalline systems. This study represents the first systematic 73 Ge NMR investigation of solids, and shows that valuable structural information can be obtained in favorable cases.
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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) | 0.000 | 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 | 0.000 |
| 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".