Trends in hyperfine coupling constants and electron‐spin <i>g</i> factors for X\documentclass{article}\pagestyle{empty}\begin{document}$^{2}\Sigma^{+}_{(g,u)}$\end{document} diatomics with 1,3, and 5 valence electrons
Bibliographic record
Abstract
Abstract A comparison of electron spin resonance (ESR) parameters calculated for X2Σ(g,u)+ diatomic radicals is presented, including Li2+, LiK+ with one valence electron (VE); Li2−, LiK−, LiBe, LiCa, LiB+, LiGa+, Be2+, and BeCa+ with 3 VEs; and B2+, BGa+ with 5 VEs. The Aiso and Adip constants are studied using 6‐311+G(2df) basis sets and several methods (UHF, CISD, MP2, B3LYP, PW91PW91). For the s‐rich radicals with 1 and 3 VEs, it is found that Aiso≫Adip≈0, whereas for those of pσ‐type (such as LiB+/LiGa+ with 3 VEs, and all present 5 VE radicals), the values of Aiso and Adip are generally similar. The electron‐spin g factors are calculated using perturbation expansions up to second order, a Hamiltonian based on Breit–Pauli theory, and correlated (MRCI) wave functions. All radicals have negative values of Δg∥ and Δg⊥. The sum‐over‐states expansions for Δg⊥ are dominated by the coupling with just one or two 2Π excited states. The Δg⊥'s of the first‐row radicals Li2+, Li2−, Be2+, LiBe, LiB+, and B2+ are about −60, −5, −120, −215, −3290, and −1300 ppm, respectively, while for the mixed first/third‐row counterparts LiK+, LiK−, BeCa+, LiCa, LiGa+, and BGa+ they are about −1200, −2480, −1000, −7840, −93700, and −800 ppm, respectively. These results show the strong influence heavier atoms with larger spin‐orbit constants have on g⊥ shifts. The smaller Δg⊥ of BGa+ (when compared with B2+) is caused by the 3σ→1π and 3σ→2π excited states contributing positively and negatively, respectively, to this shift. Such positive contribution is at variance with the rule stating that an excitation of type σ→π (SOMO→virtual MO) should contribute negatively. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 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) | 0.004 | 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".