Bonding in Nb3O, Nb3S and Nb3Se: A topological analysis of the electrostatic potential
Bibliographic record
Abstract
The structures of different neutral and cationic isomers of Nb3O, Nb3S and Nb3Se were optimized within the framework of Kohn–Sham density functional theory. For Nb3O, neutral and cationic, the lowest minimum is a planar C2v structure with an edge-bound oxygen atom. The binding energy of the oxygen to the Nb3 cluster is 184.9 kcal/mol, 185.4 kcal/mol for the cationic system. For Nb3S and Nb3Se, neutral and cationic, the lowest minima are three-dimensional structures. The corresponding binding energies are 137.9, 138.1, 131.8 and 132.3 kcal/mol for Nb3S, Nb3S+, Nb3Se and Nb3Se+, respectively. In order to explain the different ground state structures of Nb3O, on the one hand, and Nb3S and Nb3Se, on the other, in terms of the nature of the bonding in each of them a topological analysis of the molecular electrostatic potential was performed. The different relative stabilities of two- and three-dimensional structures can be explained on the basis of bond critical points in the molecular electrostatic potential.
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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 | 0.001 | 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".