In Situ High-Pressure and Low-Temperature Study of Ammonia Borane by Raman Spectroscopy
Bibliographic record
Abstract
As a promising hydrogen storage material, ammonia borane was investigated at simultaneous high pressures (up to 15 GPa) in a diamond anvil cell and at low temperatures (down to 80 K) using a cryostat by in situ Raman spectroscopy. When ammonia borane was cooled from room temperature to 220 K at near ambient pressure, an expected phase transformation from I 4 mm to Pmn 2 1 was observed. Then the sample was compressed to 15 GPa isothermally at 180 K. Three pressure-induced structural transformations were observed as evidenced by the change in the Raman profile as well as the pressure dependence of the major Raman modes. The decompression and warming-up experiments suggest that these pressure–temperature (P–T)-induced transformations are reversible. These observations, together with factor group analysis, allowed us to examine the possible structures of the new high-pressure phases and the nature of phase transitions. Raman measurements from multiple runs covering various P–T paths, when combined with previously established room-temperature and high-pressure data, enabled the updating of the P–T phase diagram of ammonia borane in the pressure region of 0–15 GPa and the temperature region of 80–350 K.
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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".