Nonlinear instability of density-independent orbital-free kinetic-energy functionals

Abstract

We study in this article the mathematical properties of a class of orbital-free kinetic-energy functionals. We prove that these models are linearly stable but nonlinearly unstable, in the sense that the corresponding kinetic-energy functionals are not bounded from below. As a matter of illustration, we provide an example of an electronic density of simple shape, the kinetic energy of which is negative. © 2005 American Institute of Physics.