A site-specific comparative study of Au<sub>102</sub> and Au<sub>25</sub> nanoclusters using theoretical EXAFS and <i>l</i>-DOS
Bibliographic record
Abstract
Recent advances in Au–thiolate nanocluster synthesis have allowed the total structural determination of several nanoclusters by X-ray crystallography. The high-precision structural information of these nanoclusters enables atomic site-specific analysis of local structure and electronic character. In this work, a site-specific comparative study of Au 102 (SR) 44 and Au 25 (SR) 18 was conducted to elucidate the size and site effects on the local environment and electronic character of their common surface structural unit, the –SR–Au–SR–Au–SR– “double-staple” motif. Simulation of the pseudo-radial distribution function from extended X-ray absorption fine structure (EXAFS) shows a significant difference in their local environments despite their identical geometric shape. Local density of states (l-DOS) calculations consistently reveal the difference in their electronic characters for gold d-electron density and d-DOS position. These differences are then related to the unique aurophilic interactions and size- or site-dependent electronic character of Au atoms in the double-staple motif. The differing local structure and electronic behaviour of the “double-staple” motif in Au 102 (SR) 44 and Au 25 (SR) 18 highlight the significance of both size and site effects on the surface structure and electronic property of Au–thiolate nanoclusters. The theoretical results may also be useful in the interpretation of future experimental XAFS and X-ray photoelectron spectroscopy (XPS) data of these nanoclusters.
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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 | 0.001 | 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 | 0.001 |
| 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".