Introduction of a New Theory for the Calculation of Magnetic Coupling Based on Spin–Flip Constricted Variational Density Functional Theory. Application to Trinuclear Copper Complexes which Model the Native Intermediate in Multicopper Oxidases
Bibliographic record
Abstract
We have introduced a new method for the calculation of spin-exchange between weakly interacting electron spins on different metal centers. The method is based on spin-flip constricted variational density functional theory (SF-CV-DFT). The application of SF-CV-DFT to two trinuclear systems [Cu3(L)(μ3-O)](4+) and [(L')3]Cu3(μ-OH)3](3+) revealed that SF-CV-DFT affords exchange coupling constants that are similar to the values obtained by the traditional broken-symmetry (BS) scheme for the same functional. The BHandHLYP functional affords for both systems the best fit to experiment and results from high-level theory in the case of BS-DFT as well as SF-CV(2)-DFT. All methods and functionals predict [Cu(L)(μ3-O)](4+) to be ferromagnetic and the [(L')3Cu3(μ-OH)3](3+) system to be antiferromagnetic. The SF-CV(2)-DFT method is not only able to evaluate exchange coupling constants, it can in addition calculate the full multiplet spectrum with complete use of spatial symmetry. Further, in its restricted formulation, calculations can be carried out with use of full spin-symmetry without spin-contamination.
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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 | 0.002 | 0.001 |
| 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".