Effects of Electron Correlation upon Molecular Interactions. Correction of the Electrostatic Interaction between DNA Bases
Journal of Molecular Structure: TheoChem
A procedure is advanced for correcting the electrostatic portion of the interaction energy for the effects of intramolecular electron correlation. This expression, which specifically treats the dipole-dipole term, involves the interaction between the Hartree-Fock dipole moment of one subunit and the second-order perturbation correction of its partner (plus the converse). The algorithm is tested on 28 different DNA base pairs, whose interaction energies have been evaluated previously as a sum of the (superposition-corrected) SCF interaction plus the (London) dispersion energy. While the correlation correction is negligible for certain pairs, it is quite sizable in others, in one case lowering the long-range dipole-dipole interaction energy by 27%. On the other hand, the poor convergence of the multipole expansion at equilibrium separation leads to unsatisfactory results at this geometry. It is suggested that a distributed multipole approach would yield superior results over a wide range of intermolecular distance.
Effects of Electron Correlation upon Molecular Interactions. Correction of the Electrostatic Interaction between DNA Bases M. M. Szczesniak, S. Scheiner and P. Hobza J. Mol. Struct., Theochem, 1988 179, 177-184.