A b i n i t i o extended Hartree–Fock calculations
- 15 August 1981
- journal article
- research article
- Published by AIP Publishing in The Journal of Chemical Physics
- Vol. 75 (4), 1888-1892
- https://doi.org/10.1063/1.442212
Abstract
Ab initio calculations are reported for the isotropic hyperfine coupling constants for sigma (vinyl and ethynyl) and nonconjugated pi (methyl) radicals using the unrestricted, projected, and extended Hartree–Fock methods. It is found that quartet state annihilation procedures closely approximate the results obtained by full projection of the UHF wave function using an STO‐3G basis set. The extended Hartree–Fock method is discussed to explain why it overestimates the spin polarization mechanism. Possible alternatives to the UHF method are discussed.Keywords
This publication has 26 references indexed in Scilit:
- Evaluation of molecular integrals over Gaussian basis functionsThe Journal of Chemical Physics, 1976
- Influence of spin contamination and basis set on electrostatic potential and Hfs coupling constants of organic radicalsTheoretical Chemistry Accounts, 1976
- Matrix formulation of the generalized Hartree‐Fock methodsInternational Journal of Quantum Chemistry, 1974
- Ab initio UHF calculations. Part 8.—Spin contamination in the cyanide radicalJournal of the Chemical Society, Faraday Transactions 2: Molecular and Chemical Physics, 1972
- Ab initio UHF calculations. Part 7.—Possible evidence for environmental effects on the radicals BH–3, CH3and NH+3Journal of the Chemical Society, Faraday Transactions 2: Molecular and Chemical Physics, 1972
- Molecular orbital theory of the electronic structure of organic compounds. X. Systematic study of geometries and energies of AHn molecules and cationsJournal of the American Chemical Society, 1971
- Molecular orbital theory of the electronic structure of organic compounds. VI. Geometries and energies of small hydrocarbonsJournal of the American Chemical Society, 1971
- Ab initio UHF calculations. Part 1.—Interaction of hydrogen atoms with alkali metal ionsTransactions of the Faraday Society, 1970
- Molecular orbital theory of the electronic structure of organic compounds. I. Substituent effects and dipole momentsJournal of the American Chemical Society, 1967
- Quantum Theory of Many-Particle Systems. III. Extension of the Hartree-Fock Scheme to Include Degenerate Systems and Correlation EffectsPhysical Review B, 1955