Abstract
Using pseudopotential theory many electron correlation effects have been investigated on the energetics of single vacancies in the simple metals, sodium and aluminum. For each metal the effective interionic potential was generated by using the nonlocal optimized model pseudopotential of shaw (1968-70) and the recent selfconsistent treatment of electron correlations in electron liquid by vashishta and singwi (1972). Many electron correlation effects have been demonstrated by considering three other dielectric functions, and the effects of locality by taking two local potentials, screened with the new dielectric function.