The nuclear spin resonance spectrum of Al²⁷ in spodumene
Bibliographic record
Abstract
Using the techniques of radio-frequency resonance spectroscopy, experimental studies of the nuclear spin resonance spectrum of Al²⁷ in single crystals of spodumene (LiAl(SiO₃)₂) have been carried out over a wide-range of externally applied magnetic field. In spodumene, interactions of the magnetic dipole moment with an external magnetic field, and also interactions of the electric quadrupole moment with the crystalline electrostatic field gradient can affect the energies of Al²⁷ nuclei. We define R as the ratio of magnetic to electrostatic interaction energies. The object of this thesis has been to measure experimentally a nuclear resonance spectrum over a wide enough range of magnetic field to link the regions where R is much greater than or much less than unity. Much experimental data is available in the literature for crystals where R differs appreciably from unity, but no experimental results have been given before for the intermediate region where R is of the order of unity and where the spectrum is more complex. Using data obtained from high field measurements in spodumene by Petch and Cranna, Lamarche has calculated energy levels by exact diagonalization of the Hamiltonian over a wide range of R values for a particular orientation of the spodumene crystal in a magnetic field. Calculations for other orientations have been made using electronic computers at the University of Toronto and at the University of British Columbia. Several of the predicted resonances have been observed. One transition has been observed over a range of magnetic field covering the region from R much less than unity to R much greater than unity. Resonance frequencies observed have been in good agreement with calculated transition frequencies. A new method of using a knowledge of the spin eigenstates to predict signal voltage for an induction spectrometer has been checked at values for R of the order of unity. It gives good agreement with experimental signal voltage measurements. Pure quadrupole transitions have been observed in spodumene at 751.5 kc and 793.5 kc with an estimated probable error of 2 kc, using an induction spectrometer with Zeeman modulation. These measurements are the lowest frequency pure quadrupole resonances reported to date.
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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 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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".