Dynamical Electron Correlation Within Hartree-Fock Limitation

Abstract

Aim: Calculation of dynamical electron correlation energy within Hartree Fock formalism to achieve post Hartree Fock accuracy. Achievement: Using intermediate Hamiltonian technique and perturbation methodology we can construct a weave equation which on projection gives very simple equation for correlation energy. Correlation energy only depends on the amount of perturbation. This method is applied for few small molecules. It is found that this method produces very accurate results which is comparable to CCSD method. Conclusion:The present method which is termed as Extended Hartree Fock (EHF) method is proved to be a very good tool for electronic structure theory as its computational requirement is equivalent to HF method but its accuracy is comparable to Coupled Cluster based methods.