| Autor: |
Ferreras KN; Department of Chemistry, Iowa State University and Ames National Laboratory, Ames, Iowa 50011, United States., Gordon MS; Department of Chemistry, Iowa State University and Ames National Laboratory, Ames, Iowa 50011, United States. |
| Jazyk: |
angličtina |
| Zdroj: |
Journal of chemical theory and computation [J Chem Theory Comput] 2024 Jul 09; Vol. 20 (13), pp. 5487-5496. Date of Electronic Publication: 2024 Jun 25. |
| DOI: |
10.1021/acs.jctc.4c00322 |
| Abstrakt: |
The SF-ORMAS-PDFT (spin-flip occupation restricted multiple active space-pair density functional theory) approach combines the SF-ORMAS-CI method with the MC-PDFT method to treat both static and dynamic correlation in multiconfigurational systems. The static correlation description is generated via the spin-flip approach, which uses a high-spin single reference determinant to treat excited states with multiconfigurational characters. The on-top pair density functional theory uses a translation scheme applied to GGA density functionals. The SF-ORMAS-PDFT scheme has also been combined with virtual valence orbitals (VVO), a well-defined subspace of the virtual molecular orbitals, giving rise to significant speedups relative to the use of the full virtual space. The accuracy of the SF-ORMAS-PDFT method is tested by calculating 65 vertical excitation energies of 12 small- and medium-sized organic molecules. The SF-ORMAS-PDFT vertical excitation energies calculated with VVOs are comparable to those calculated with the full virtual space. The SF-ORMAS-PDFT/6-31G(d) level of theory predicts the rotational barrier of ethylene to be 65.5 and 65.9 kcal/mol, with full virtual space and VVOs, respectively. These predicted barrier heights compare well with the experimental value of 65 kcal/mol. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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