Energetics of 1,<i>n</i>‐didehydro‐polyene diradicals and performance of reduced multireference coupled‐cluster method
Bibliographic record
Abstract
Abstract The reduced multireference coupled‐cluster method with singles and doubles (RMR CCSD) and its RMR CCSD(T) version are employed to study the energetics of 1, n ‐didehydro‐polyenes. The RMR CCSD method accounts for quasi‐degeneracy by exploiting a multireference (MR) CISD wave function as an external source of the most important (primary) triples and quadruples while the subsequent perturbative correction for the secondary triples leads to RMR CCSD(T). The resulting energies are compared with those yielded by the standard single‐reference (SR) CCSD and CCSD(T) approaches. We first determine the optimal geometry for each species considered. Using the CC methods just mentioned we then compute the energy of the lowest‐lying singlet and triplet states, the implied singlet‐triplet splitting, and determine the spin multiplicity of the ground state. We point out the relationship between the degree of the diradical character, the extent of quasi‐degeneracy or the MR nature of the state considered, the distance separating the radical centers and, finally, the size of the largest doubly excited cluster amplitude in the CC wave functions. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
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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) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.004 | 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".