Estimation of molecular correlation energies from semi-transferable orbital correlation energies

Abstract

The transferability of the orbital correlation energies, defined as the sum of pair correlation energies between an electron and all others, have been investigated. A semi-transferability is observed among similar molecules. Using these semi-transferable orbital correlation energies, the total correlation energies of CO₂, CH₃OH, CH₂O, HCOOH and some non-cyclic hydrocarbons are estimated and compared with the direct semi-empirical calculation results. The largest discrepancy is found to be < 3 % of the total correlation energy.