Polarization effects in the excitation and emission of Fe<sup>3+</sup>in orthoclase and their relevance to the determination of lattice sites of unknown defects
Bibliographic record
Abstract
A method was recently proposed for determining possible lattice sites of an unknown defect from polarization effects in its optical transitions. In this paper the method is tested using the optically excited 1.77 eV (700 nm) fluorescence of Fe(3+) ions which predominantly occupy the T1 sites in orthoclase feldspar. The emission intensity depended on the polarization of the exciting photons and the emission was itself polarized. Two pairs of crystal field symmetry directions were deduced from polarization data for each of the transitions at 1.77, 2.79 and 3.26 eV, and one pair was aligned with symmetry axes in the average geometry of the four anions around the T1 sites. An analysis of EPR data for Fe(3+) ions in feldspar showed that there was a symmetry axis in the crystal field similar to one of those deduced from the polarization data. Group theory calculations were used to determine if the transitions were dipolar-a major assumption of the method. Three symmetries (S(4), C(2v) and C(2)) were found to lead to dipolar transitions consistent with the excitation results, and four (D(2), C(3), C(2) and C(s)) were consistent with a 1.77 eV dipolar emission.
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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) | 0.000 | 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 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".