Theoretical condiserations regarding the existence of PsO and PsS+

At has been proposed from experimental studies and in analogy with hydrogen compounds that PsO may be an entity of some importance, or an intermediate, in the reaction of positronium, Ps, with aqueous oxyacid species such as H₂PO^?₄, HSO^?₄, ClO^?₄, and NO^?₃. This communication explores the stability of PsO and PsS, or 0^?: e⁺] and S^?:e⁺], respectively, relative to dissociation into Ps and O(³P) or S(³P) on the basis of restricted Hartree-Fock calculations for the PsO and PsS systems and certain correlation correction arguments. We obtain a reasonable lower estimate of the dissociation energy to Y + Ps of ? ?0.47 eV for PsO and ? ?0.70 eV for PsS. It is suggested that a modest correlation correction to the positron affinity (PA) of O^? would very probably lead to a bound state system for PsO.