MANY-ELECTRON EXPLICITLY CORRELATED GAUSSIAN FUNCTIONS .2. GROUND-STATE OF THE HELIUM MOLECULAR ION HE-2(+)

Explicitly correlated Gaussian functions have been used to compute variationally the Born-Oppenheimer (B-O) potential energy curve for the ground 2Σu+ state of He2+. The energy values are much lower than all previously reported over the whole range of the internuclear distance R. The strict lower bound for the binding energy De amounts to 2.4730 eV and the true value (within the B-O approximation) is estimated to be 2.4742±0.0006 eV. © 1995 American Institute of Physics.