KINETIC-ENERGY DENSITY-FUNCTIONAL - ATOMS AND SHELL STRUCTURE

We present a nonlocal kinetic-energy functional which includes an anis otropic average of the density through a symmetrization procedure. Thi s functional allows a better description of the nonlocal effects of th e electron system. The main consequence of the symmetrization is the a ppearance of a clear shell structure in the atomic density profiles, o btained after the minimization of the total energy. Although previous results with some of the nonlocal kinetic functionals have given incip ient structures for heavy atoms, only our functional shows a clear she ll structure for most of the atoms. The atomic total energies have a g ood agreement with the exact calculations. Discussion of the chemical potential and the first ionization potential in atoms is included. The functional is also extended to spin-polarized systems.