Positronic lithium, an electronically stable Li-e(+) ground state

Calculations of the positron-Li system were performed using the stochastic variational method, yielding a minimum energy of -7.53208 hartree for the L = 0 ground state. In contrast with previous calculations of this system, the system was found to be stable against dissociation into the Ps + Li+ channel with a binding energy of 0.002 17 hartree; it is therefore electronically stable. This is the first instance of a rigorous calculation predicting that it is possible to combine a positron with a neutral atom to form an electronically stable bound state.