Identification of pyrite valence band contributions using synchrotron-excited X-ray photoelectron spectroscopy
Bibliographic record
Abstract
The major contributions to the pyrite valence band have been identified experimentally by monitoring XPS valence band signal intensity as a function of photon (X-ray source) energy. The S-S σ and σ* orbitals are located at about 13 and 16 eV binding energy and are almost exclusively derived from S 3s-S 3s mixing; there is no experimental evidence for a S 3p contribution to these molecular orbital (molecular orbital) values as required for sp3 hybridization. Fe-S σ (Fe 3deg-S 3pz derived) and Fe-S π and π* (Fe 3dt2g-S 3px,y derived) molecular orbitals are identified at Binding Energies (B.E.) less than 8 eV, and are consistent with energies calculated by Eyert et al. (1998). Fe-S π molecular orbital contributions are located in the valence band between about 1.8 and 3 eV and Fe-S π* molecular orbitals contribute between about 0.7 to 1.5 eV binding energy. Contributions observed at the top of the valence band and concentrated between the Fermi level and about 0.6 eV B.E. may be derived from Fe 3deg (non-bonding) orbitals. The experimental data are consistent with these non-bonding contributions being derived from surface Fe species (Fe electronic surface states), and perhaps represent the Fe 3deg "dangling bonds" produced by rupture of Fe-S σ bonds during fracture. The conformity of spectral assignments based on experimental data with band theoretical calculations (of Eyert et al. 1998, using a basis set appropriate to pyrite) indicates that the essential aspects of the pyrite valence band are understood and energetically quantified. Additional study is required to identify positively.
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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 | 0.000 | 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".