A DFT study on the electronic and redox properties of [X <sub>8</sub> V <sub>14</sub> O <sub>50</sub> ] <sup> <i>n</i> – </sup> (X = Si <sup>IV</sup> , Ge <sup>IV</sup> , P <sup>V</sup> , and As <sup>V</sup> )
Bibliographic record
Abstract
The electronic and redox properties of the title polyanions have been calculated by means of density functional theory (DFT). These were unrestricted open-shell systems with electronic configuration of d 1 of V. In this behalf, energies and compositions of α-LUMO, β-LUMO, α-HOMO, and β-HOMO were also analyzed. First of all, electronic and redox properties of vanadosilicate [Si 8 V 14 O 50 ] 12– (system 1) were calculated and then Si IV was substituted with Ge IV , P V , and As V for further investigations of systems 2, 3, and 4, respectively. The substitution greatly modifies the electronic properties as α-LUMOs are quite different in all the studied systems. The α-LUMO is mainly composed of V and O in system 1, V and Ge in system 2, V and O in system 3, and As, O, and V in system 4. The alpha HOMO–LUMO energy gaps are greatly reduced in systems 2, 3, and 4 as compared with system 1. The system 4 [As 8 V 14 O 50 ] 4– has minimal value of total bonding energy, whereas system 2 [Ge 8 V 14 O 50 ] 12– has maximal, so energetically system 4 is more favourable than the others. After the first reduction, α-LUMO in [Si 8 V 14 O 50 ] 14– is made up of V and Si, β-LUMO in [Ge 8 V 14 O 50 ] 13– is concentrated on V and Ge, β-LUMO in [P 8 V 14 O 50 ] 5– is composed of V only, whereas β-LUMO in [As 8 V 14 O 50 ] 5– is delocalized over V, O, and As with almost the same contribution of all three atoms.
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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 | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.004 | 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".