Raman and infrared spectra to monitor the phase transition of natural kyanite under static compression
Bibliographic record
Abstract
Abstract The stability of kyanite Al2SiO5 at high pressure is of significance in understanding the fate of the subducted crust and how they recycle within the Earth. Thus, in situ high‐pressure vibrational spectra of natural kyanite are presented. The shift amplitudes of the measured modes dependent on pressure manifest the contraction of the AlO bond bears the most compression of kyanite. At 9.7 GPa, a first‐order phase transition to kyanite‐II occurs, which is distinguished by changes occurred in the entire spectral region, including the pressure dependences of the modes, the wavenumber jumps of some peaks, the splitting of a SiO symmetric stretching band, and the emergence of new modes. A Raman mapping image is collected illustrating kyanite and kyanite‐II in coexistence at 10.0 GPa. Emphasize that, as is revealed by the infrared spectra, a part of HO···O distance becomes elongated after the transformation. At higher pressure up to 18.6 GPa, the Raman spectra disclose little effects associated with further transformations. Finally, releasing pressure to ambient leads to recovery of pure kyanite. Our results mark a lowest pressure limit of the change in the intermolecular and intramolecular bonding of kyanite and shed new lights on the crystal chemistry of aluminosilicate under mantle pressures.
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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) | 0.002 | 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".