Aliaaa A. Hassan
Abstract: The energies that evaluated for atomic and molecular systems have a huge important in theatrical and practical calculations and of a big consider in studding the properties of these system. There is clear the effects of correlation weave function in field studding different atomic and molecular structures and given reasons for many behaving of calculation properties of the system sin various physics field such solid state, materials and atomic, molecular physics.Through the recent research, there is calculated the electron correlation in two electrons system by using a new function, it was found in this study.That represent the correlation function which use configuration interaction principle. Correlation energy is evaluated for two electron (e. i He atom ) as a close example.The energy value of research is compared with experimental energy value, with that value was evaluated from famous correlated ( like Wiss 1961 ) and with energy value was calculated from best uncorrelated function that is Hartree Fock wave function.This results point to wellness behave the new correlated function.
Keywords: correlation, correlation energy, configuration interaction, HF approximation, uncorrelated wave function