New Insights into the Bonding Properties of [Ag25(SR)18]- Nanoclusters from X-ray Absorption Spectroscopy
Bibliographic record
Abstract
Atomically precise metal nanoclusters have attracted significant interest due to their molecule-like properties. [Ag25(SR)18]- is one of the Ag nanoclusters having a unique structure similar to its Au counterpart but different from most other Ag nanoclusters. In this study, a new five-shell fitting method was developed to analyze the extended X-ray absorption fine structure (EXAFS) spectra of [Ag25(SR)18]- to provide more insights into its bonding properties. This new method was successfully applied to compare the bond lengths as the temperature changed from 300 K to 90 K. Interestingly, the metal core of [Ag25(SR)18]- shows negative thermal expansion behaviour that is not observed for Au25(SR)18. These unique bonding properties of [Ag25(SR)18]- could be related to the Ag4 tetrahedral units found in the metal core, which are absent in Au25(SR)18. These new findings about its bonding properties can provide a better understanding of the structure-property relationship of [Ag25(SR)18]-. This new EXAFS analysis method could be applied to gain insights into the bonding properties of other metal 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 | 0.000 | 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 | 0.001 | 0.001 |
| 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 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".