Diagonal perturbative triple corrections to the general‐model‐space state‐universal coupled‐cluster method: Are they warranted and useful?
Bibliographic record
Abstract
The recently developed general‐model‐space (GMS) state‐universal (SU) coupled‐cluster (CC) approach, together with its version corrected for triples via a single‐reference (SR) CCSD(T)‐type correction of the diagonal elements of the effective Hamiltonian, is applied to several molecular electronic structure problems in order to assess their performance and the role of triples. These results are compared with an alternative handling of higher‐than‐pair clusters via the externally corrected SU CCSD method, denoted (M,N)‐CCSD, which employs N wave functions of the M‐reference CISD as an external source for N‐reference SU CCSD. These methods are applied to the problem of bond breaking in the ground and excited states of the F2 and HF molecules, where the high‐spin triplet component is also handled via the SR CCSD method. We further examine the vertical excitation energies of water and the basic spectroscopic constants (equilibrium geometries, harmonic frequencies, and excitation energies) for several low‐lying states of oxygen. The results are encouraging and are discussed from the viewpoint of the applicability and usefulness of perturbative‐type triple corrections.
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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 | 0.006 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.003 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 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".