Density-functional approach to one-positron and neutral-atom bound states

Binding of a positron to a neutral atom is explored within the premise of a three-component density-functional theory. Within this regime, employing model electron-positron correlation potentials (which are crucial for binding), it turns out that the systems {sup 2}[Li;e{sup +}], {sup 2}[Na;e{sup +}], and {sup 2}[K;e{sup +}] exhibit stability with respect to neutral-atom{endash}positron dissociation, but are unstable with respect to positronium-cation dissociation, while the species {sup 3}[He;e{sup +}], {sup 1}[Be;e{sup +}], {sup 2}[F;e{sup +}], {sup 1}[Mg;e{sup +}], {sup 2}[Cl;e{sup +}], and {sup 1}[Ar;e{sup +}] exhibit stability with respect to both these dissociation modes. The indispensability of the inclusion of the electron-positron correlation for atom-positron binding is also emphasized. {copyright} {ital 1996} {ital The American Physical Society}