Total energy evaluation in the Strutinsky shell correction method

摘要

We analyze the total energy evaluation in the Strutinsky shell correction method(SCM)of Ullmo et al.[Phys.Rev.B 63,125339(2001)],where a series expansion of the total energy is developed based on perturbation theory.In agreement with Yannouleas and Landman [Phys.Rev.B 48,8376(1993)],we also identify the first-order SCM result to be the Harris functional [Phys.Rev.B 31,1770(1985)].Further,we find that the second-order correction of the SCM turns out to be the second-order error of the Harris functional,which involves the a priori unknown exact Kohn-Sham(KS)density,pho_(KS)(r).Interestingly,the approximation of pho_(KS)(r)by pho_(out)(r),the output density of the SCM calculation,in the evaluation of the second-order correction leads to the Hohenberg-Kohn-Sham functional.By invoking an auxiliary system in the framework of orbital-free density functional theory,Ullmo et al.designed a scheme to approximate pho_(KS)(r),but with several drawbacks.An alternative is designed to utilize the optimal density from a high-quality density mixing method to approximate pho_(KS)(r).Our new scheme allows more accurate and complex kinetic energy density functiohals and nonlocal pseudopotentials to be employed in the SCM.The efficiency of our new scheme is demonstrated in atomistic calculations on the cubic diamond Si and face-centered-cubic Ag systems.