Second Bound State of PsH

The existence of a second bound state of PsH that is electronically stable and also stable against positron annihilation by the normal 2γ and 3γ processes is demonstrated by explicit calculation. The state can be found in the ^2,4S^o symmetries with the two electrons in a spin-triplet state. The binding energy against dissociation into the H(2p)+Ps(2p) channel was 7.03×10^-4  hartree. The dominant decay mode of the states will be radiative decay into a configuration that autoionizes or undergoes positron annihilation. The NaPs system of the same symmetry is also electronically stable with a binding energy of 1.514×10^-3  hartree with respect to the Na(3p)+Ps(2p) channel.