ABILITY OF NONPERTURBATIVE DENSITY-FUNCTIONAL THEORIES TO STABILIZE ARBITRARY SOLIDS - COMMENT

Kyrlidis and Brown [Phys. Rev. A 44, 8141 (1991)] assert that the modi fied weighted density approximation of Denton and Ashcroft [Phys. Rev. A 39, 4701 (1989)] may possess two solutions for the effective densit y. We show here that it has either one well-defined solution or none, the latter when the physical structure that is attempting to be mapped into an effective liquid does not exist. The absence of a solution wh en none is expected physically cannot, therefore, be characterized as a defect of the theory.