Multireference coupled‐cluster methods for ground and low‐lying excited states. A benchmark illustration on CH <sup>+</sup> potentials
Bibliographic record
Abstract
Abstract Multireference (MR), general‐model‐space (GMS), state‐universal (SU) coupled‐cluster (CC) method that considers singly (S) and doubly (D) excited cluster amplitudes relative to the reference configurations spanning the model space (GMS SU CCSD), as well as its externally corrected (ec) version ( N , M )‐CCSD that uses N ‐reference MR CISD as an external source of higher‐than‐pair cluster amplitudes in a M ‐reference GMS CCSD, are used to investigate low‐lying states of the CH + ion. Relying on a simple ab initio model that enables a comparison with the exact full configuration interaction energies, the performance of the GMS‐based methods is assessed in the whole relevant range of internuclear separations. It is shown that the ec ( N , M )‐CCSD version provides best results for both the singlet and the triplet states considered. For triplets, the use of high‐spin ( M S = 1) references is to be preferred. The GMS‐based MR SU CC results for the ten low‐lying states of CH + clearly indicate the usefulness and reliability of these approaches. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
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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".