CALCULATION OF POSITRONIUM COMPOUNDS, PSLI, PSF, AND PSCL, BY 2ND-ORDER VARIATIONAL PERTURBATION METHOD

Correlation, positron ionization, and positronium (Ps) binding energies for the ground state (S-2,S-1) Of PsLi, PsF, and PsCl together with the excited state (P-2,P-1) of PsF and PsCl are calculated by the second-order variational perturbation method with partial wave expansion. Estimated positronium binding energies for PsLi(S-2,S-1), PsF(S-2,S-1), PsCl(S-2,S-1), PsF(P-2,P-1), and PsCl(P-2,P-1) are -2.19, 2.24, 1.62, -0.16, and -0.05 eV, respectively. The Ps binding energies of PsF(S-2,S-1) and PsCl(S-2,S-1) are in good agreement with the ones estimated by quantum Monte Carlo calculation and also with experimental ones.