Explicit energy density functional for the Crandall two-electron model atom with harmonic confinement and inverse square law inter-particle repulsion

Though density functional theory is already developed in useful practical numerical forms, no explicit simple ground-state energy density functional exists. Here, towards establishing such a theory, we present the ground-state energy of the Crandall et al.'s two-electron spin-compensated model atom in terms of del(2)rho(r)/rho(r) evaluated at r = 0, where rho(r) is the electron density