KOHN-SHAM BOND LENGTHS AND FREQUENCIES CALCULATED WITH ACCURATE QUADRATURE AND LARGE BASIS-SETS
CHEMICAL PHYSICS LETTERS, 199 (6):
551--556 (1992)Abstract
We report calculations of bond lengths and frequencies using Kohn- Sham theory, defined as replacing the exchange term in the Hartree-Fock self-consistent field procedure by Potentials of density functional theory. Several functionals are tested including the local density approximation to the exchange energy, Becke's non-local correction to the exchange, the Vosko-Wilk-Nusair functional for correlation with Perdew's non-local correction to the correlation energy and the Lee-Yang-Parr correlation functional. High accuracy quadrature is used, which enables the gradient of the energy to be calculated straightforwardly. The results are compared to Hartree-Fock theory and to hybrid DFT methods based on the Hartree-Fock density. On average, bond lengths from the hybrid method are much better than SCF bond lengths, and often better than those from second-order Moller-Plesset theory. The Kohn-Sham bond lengths are rather long, but improve as the basis set is increased, and for large basis sets bond lengths, dipole moments and frequencies appear on to be a significant improvement over SCF theory.