Modeling Localized Electron-Pair Correlation Energies
by Rauhut, G.; Boughton, J. W.; Pulay, P.
Localized Fair correlation energies of closed shell organic molecules have been modeled by a backpropagation neural network approach. The contributions of Boys localized pairs to the total correlation energy are predicted using geometrical and simple electronic information of the participating orbitals at the ab initio Hartree-Fock level. We have concentrated on modeling the numerous distant (dispersionlike) orbital interactions. Localized pair correlation energies have been calculated at the Moller-Plesset second order level using the 6-31G(d,p) basis for 65 organic molecules, containing 9458 pair energies. A neural network was trained to reproduce these pair energies from readily accessible properties of the localized orbitals. The correlation energies calculated-by the net-based formula compare well with conventional MP2 results for 10 test molecules.