First-principles calculations of structural, electronic, vibrational, and magnetic properties of C60 and C48N12: A comparative study
Bibliographic record
Abstract
The structural, electronic, vibrational, and magnetic properties of the C48N12 azafullerene and C60 are comparatively studied from the first-principles calculations. Full geometrical optimization and Mulliken charge analysis are performed. Electronic structure calculations of C48N12 show that the highest occupied molecular orbital (HOMO) is a doubly degenerate level of ag symmetry and the lowest unoccupied molecular orbital (LUMO) is a nondegenerate level of au symmetry. The calculated binding energy per atom and HOMO-LUMO energy gap of C48N12 are about 1 eV smaller than those of C60. Because of electron correlations, the HOMO-LUMO gap decreases about 5 eV and the binding energy per atom increases about 2 eV. The average second-order hyperpolarizability of C48N12 is about 55% larger than that of C60. Our vibrational frequency analysis predicts that C48N12 has 58 infrared-active and 58 Raman-active vibrational modes. Two different methods for calculating nuclear magnetic shielding tensors of C60 and C48N12 are compared, and we find that C48N12 exhibits eight C13 and two N15 NMR spectral signals. Our best-calculated results for C60 are in excellent agreement with experiment. Our results suggest that C48N12 has potential applications as semiconductor components, nonlinear optical materials, and possible building blocks for molecular electronics and photonic devices.
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.002 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.002 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.005 | 0.001 |
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".