Stability of atomic systems containing two positrons, Ps2H+, Ps2F+, and Ps2Cl+: A multireference configuration interaction approach

The multireference configuration interaction method is applied with extrapolations to atomic systems containing two positrons, Ps2H+, Ps2F+, and Ps2Cl+. The stability of these systems is examined. These systems are all stable against the lowest dissociation channel e+ + PsX. The dissociation energies to the e+ + PsX channel are, respectively, 0.574, 0.528, and 0.544 eV for Ps2H+, Ps2F+, and Ps2Cl+. Dissociation to several higher channels is also investigated.