The energy interval between the ground and the P-wave excited states of the recently discovered positronium molecule Ps2 is evaluated, including the relativistic and the leading logarithmic radiative corrections, E_{P}-E_{S}=0.181 586 7(8) a.u.. The P state, decaying usually via annihilation, is found to decay into the ground state by an electric dipole transition 19% of the time. Anticipated observation of this transition will provide insight into this exotic system.
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