Radiation-induced defects in apophyllites. I. The NH2 free radical in fluorapophyllite
Bibliographic record
Abstract
The NH2 free radical, which is one of the most studied triatomic molecules and is widely used as spin labels in biophysical and biomedical research, has not been reported in mineral lattices. Fourier-transform infrared (FTIR) spectrum supports electron-microprobe analyses that fluorapophyllite on the cavity walls in a phonolite (North Bohemia, Czech Republic) contains ammonium NH4+. Powder and single-crystal electron paramagnetic resonance (EPR) spectra of this fluorapophyllite, with and without γ irradiation, disclose at least four paramagnetic defects, including two previously reported VO2+ centers, the NH2 free radical and an oxygen-associated center. The spin-Hamiltonian parameters of the NH2 free radical have been determined from single-crystal EPR data and show that this molecule is oriented parallel to (and rapidly rotated about) the crystallographic c axis. The NH2 free radical in fluorapophyllite, most likely formed from radiolysis of the NH4+ ion, remains stable after annealing at 300 ° C, but is bleached at 340 ° C.
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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 | 0.000 |
| 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) | 0.001 | 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".