Density Functional Study of H−D Coupling Constants in Heavy Metal Dihydrogen and Dihydride Complexes: The Role of Geometry, Spin−Orbit Coupling, and Gradient Corrections in the Exchange-Correlation Kernel
Bibliographic record
Abstract
The H-D nuclear spin-spin coupling constants J(H-D) of 14 heavy transition-metal dihydrogen and dihydride complexes were calculated with density functional theory using the "zeroth-order regular approximation" (ZORA) for the one-electron operators. The applied gradient-corrected density functional was able to achieve an average agreement with experimental data that is almost comparable to what has been obtained recently with hybrid functionals [J. Am. Chem. Soc. 2004, 126, 14249]. However, a systematic overestimation of J(H-D) for complexes with short H-D distances was obtained, which could be traced back to problems of the gradient functional to describe the H-D coupling in free dihydrogen well. We implemented gradient corrections for the exchange-correlation (XC) kernel and employed a basis sets with high-exponent 1s function for the coupled hydrogens. The gradient terms in the XC kernel turned out to be very important in order to achieve reasonable agreement with experimental coupling constants. On the other hand, our study reveals that spin-orbit relativistic corrections on the H-D coupling constants are comparatively small and need not to be considered at the accuracy level of currently available "standard" density functionals. The discussion of the results highlights the strong dependence of the coupling constants on the H-D distance and the possibility of large vibrational contributions to them. We also discuss the coupling constant for the hydrogen molecule in detail because of its relevance to the coupling in dihydrogen and dihydride complexes.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.001 | 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".