Truncated version of the reduced multireference coupled-cluster method with perturbation selection of higher than pair clusters
Bibliographic record
Abstract
A general implementation of a perturbatively truncated version of the reduced multireference (RMR) coupled-cluster method with singles and doubles (CCSD) [Peris, G. et al. J Chem Phys 1999, 110, 11708]—representing the MR-CISD-based version of the so-called externally corrected CCSD—is described and tested on several molecular systems involving the dissociation of a single bond of different character (HF and F2) as well as of a triple bond (N2). The possible pitfalls of a straightforward application of a perturbative selection scheme that is based on the first-order wave function coefficients are discussed, and different selection schemes are examined. It is shown that in order to obtain a stable and reliable scheme, it is necessary to exclude from the selection process all singles (and preferably all singles and doubles) relative to the leading Hartree–Fock reference configuration and retain them in the MR CISD wave function used as the external source of higher than pair connected clusters. The benefits of using perturbatively truncated RMR CCSD based on a large active space versus a nontruncated one, relying on a small model space, are also pointed out. © 2000 John Wiley & Sons, Inc. Int J Quant Chem 80: 743–756, 2000
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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 | 0.002 |
| 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 | 0.004 | 0.001 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.005 | 0.002 |
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".