NONLOCAL KINETIC-ENERGY-DENSITY FUNCTIONALS

In this paper we present nonlocal kinetic-energy functionals T[n] with in the average density approximation (ADA) framework, which do not req uire any extra input when applied to any electron system and recover t he exact kinetic energy and the linear response function of a homogene ous system. in contrast with previous ADA functionals, these present g ood behavior of the long-range tail of the exact weight function, The averaging procedure for the kinetic functional (averaging the Fermi mo mentum of the electron gas, instead of averaging the electron density) leads to a functional without numerical difficulties in the calculati on of extended systems, and it gives excellent results when applied to atoms and jellium surfaces.