Theoretical study on the stability of PsBr and PsI with second-order correlation energies

The positronium (Ps) binding energies for the ground state (2,1S) of positronium bromide (PsBr) and positronium iodide (PsI) are calculated by second-order variational perturbation method. Estimated Ps binding energies of PsBr and PsI are 1.25 and 0.56 eV, respectively. Ps binding energy of PsI is positive value unlike result of restricted Hartree–Fock calculation (−0.45 eV), and the present result is consistent with experimental result that PsI exists.