Mechanisms for the formation of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mtext>H</mml:mtext><mml:mn>2</mml:mn></mml:msub></mml:mrow></mml:math>and<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mtext>O</mml:mtext><mml:mn>2</mml:mn></mml:msub></mml:mrow></mml:math>from x-ray irradiated dense ice
Bibliographic record
Abstract
Recent experiment [W. L. Mao et al., Science 314, 636 (2006)] has shown that when ice VII is irradiated by intense x ray it dissociates into an alloy of ${\text{O}}_{2}$ and ${\text{H}}_{2}$ at high pressure. It is proposed here that irradiation stimulates the creation of ``excess'' electrons and holes, as well as radical defects, which interact with each other to promote the dissociation. First-principles calculations on ice VII show that ${\text{H}}_{2}\text{O}$ dissociates into ${\text{H}}^{.}$ and ${\text{OH}}^{.}$ within 100 fs after core ionization. Secondary interaction of ${\text{H}}^{.}$ with an excess electron leads to the formation of an interstitial ${\text{H}}_{2}$ molecule. On the other hand, ${\text{H}}_{2}{\text{O}}_{2}$, a precursor of ${\text{O}}_{2}$, is formed when an ${\text{OH}}^{.}$ radical is in an electron-deficient environment. Direct formation of a nearly free ${\text{O}}_{2}$ is observed in a model consisting of two adjacent ${\text{OH}}^{.}$ in a highly electron-deficient environment. The theoretical results offer an atomistic insight to rationalize the pressure effect on the dissociation of water to ${\text{O}}_{2}$ and ${\text{H}}_{2}$.
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.002 | 0.003 |
| Open science | 0.003 | 0.001 |
| Research integrity | 0.002 | 0.002 |
| Insufficient payload (model declined to judge) | 0.022 | 0.005 |
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".