QUANTUM-CHEMICAL STUDY OF SIMPLE POSITRONIC SYSTEMS USING EXPLICITLY CORRELATED GAUSSIAN FUNCTIONS - PSH AND PSLI(+)

The electronic structure of positronium hydride has been studied using explicitly correlated Gaussian functions. The resulting energy consti tutes new upper bound to the exact nonrelativistic energy of PsH withi n the Born-Oppenheimer approximation. The two photon annihilation rate was computed using the optimized wave function. Preliminary results f or the positron bonded with the lithium atom indicate the stability of this system against the dissociation into Li+ cation and Ps atom. (C) 1998 American Institute of Physics.