Coupled‐perturbed Hartree–Fock treatment of infinite periodic systems: Application to static polarizabilities and hyperpolarizabilities of polydiacetylene, polybutatriene, and interacting pairs of polyacetylene chains
Bibliographic record
Abstract
Abstract Static longitudinal polarizabilities (α) and second hyperpolarizabilities (γ) are determined for three quasi‐one‐dimensional polymeric systems using a new crystal orbital coupled‐perturbed Hartree–Fock method. Calculations of α and γ for polydiacetylene and polybutatriene at two different geometries are analyzed in terms of the alternation of bond lengths along the carbon backbone. For the third polymer, polyacetylene, the treatment is applied to a pair of chains in the two different configurations that occur in a stretched fiber. The results are in marked contrast to those previously obtained for short and medium‐sized oligomers. In order to relate the pair interaction effect between infinite chains to the bulk susceptibility of the natural fiber additional finite oligomer calculations are carried out. This allows us to discuss the role of finite chain length distribution, many‐body interchain interactions, and electron correlation. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002
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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 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.002 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 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".