EXCHANGE AND CORRELATION KOHN-SHAM FUNCTIONALS FOR THE HELIUM ATOM - LOCALITY AND HOMOGENEITY

The locality and homogeneous nature of the exchange and correlation fu nctionals for the ground state of the helium atom, in the Kohn-Sham fo rmulation, are revisited. Our analysis is focused on the integrands of both functionals, although the integrated quantities are compared wit h previous results. Both functionals are not local, and the correlatio n functional is not homogeneous. To study the non-locality, a set of d ependences on the derivatives of the density, compatible with the more general constraints that must be fulfilled, is selected, We are not a ble to explain the non-local nature of the functionals. (C) 1998 Publi shed by Elsevier Science B.V. All rights reserved.