Electrostatic interpretation of the force −∂V_xc/∂r connected with the exchange-correlation potential: direct relation to single-particle kinetic energy density in Be-atom

Abstract

In a recent study by one of us [Phys. Rev. A 65 (2002) 034501], an electrostatic interpretation has been proposed for the force −∂V_xc/∂r associated with the exchange-correlation potential energy V_xc(r) in a spherical atom such as Be or Ne. Here, this proposal is employed to relate −∂V_xc/∂r directly to (a) the exact ground-state density ρ(r) (e.g., from diffraction experiments or quantum Monte Carlo simulation) and its low-order derivatives, and (b) the single-particle kinetic energy density t_s(r), calculated again from the exact ρ(r), for the example of the Be-atom. It would, of course, be important if this type of relation could be extended beyond a (1s)²(2s)² two-level single-particle configuration.