Evolution of valence electron density of compressed Na–Au alloys
Bibliographic record
Abstract
Maximum Entropy Method (MEM) analyses were performed on previously reported synchrotron x-ray powder diffraction patterns of Na-Au intermetallics from 0.8 to 60 GPa [1].The derived valence charge density distributions show gradual electron migration from electropositive Na to electronegative Au as the pressure is increased.However, the electronic interaction cannot be ascribed to a simple electron transfer process proposed for the analogous K-Ag alloy system [2].Na-Au "covalent" bonds and and electrides were identified in the low-pressure orthorhombic phase-I Na2Au The electron distribution of the higher pressure phase II Na3Au, in which Rietveld refinements failed to distinguish between a trigonal and hexagonal structure, is consistent with the hexagonal space group.Clear evidence of Au-Au and Na-Au bonds was observed in the high-pressure cubic phase-III Na3Au.Charge densities computed from density functional theory complement and support the MEM analysis.Projection of the plane wave wavefunctions into atom-centred orbitals followed by the construction of natural bind orbital and the solid state extension provided a conventional description based on the two-center two-electron and multi-center bonding scheme.
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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 | 0.001 | 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".