Approximation of the exchange-correlation Kohn-Sham potential with a statistical average of different orbital model potentials

A statistical average of different model orbital potentials is proposed as a way to model the exchange-correlation is developed using the statistical average of a model potential Kohn-Sham potential v(xc sigma). An approximat e potential v(xc sigma)(SAOP) is developed using the statistical average of a model potential y(xc sigma)(Ei) With exact asymptotics for the highest o ccupied KS orbital psi(N sigma) with a model potential v(xc)(GLB) for other occupied orbitals, which has a proper atomic shell structure. To get exact asymptotics, an exponential integral function E-1(l/x(sigma)) of the dimen sionless gradient argument x(sigma) is employed within v(xc sigma)(Ei). For the Ne atom calculations with the new model potential can, in principle, r eproduce perfectly all energy characteristics (orbital energies and the vir ial integral I-v= Sigma(sigma) integral[3 rho(sigma)(r) + r . del rho(sigma )(r)]v(xc sigma)(r)dr) of the essentially accurate v(xc sigma) for a partic ular system, as well as the slopes of v(xc sigma) in both outer and inner r egions. Atomic calculations with v(xc sigma)(SAOP) show that this model giv es a good quality of both the calculated energy E-N sigma of psi(N sigma) a nd of the calculated virial integral. (C) 1999 Elsevier Science B.V. All ri ghts reserved.