Exponentially correlated Hylleraas‐configuration interaction studies of atomic systems. II. Non‐relativistic energies of the 1 through 6 states of the Li+ ion

Abstract

AbstractThe exponentially correlated Hylleraas‐configuration interaction wave function (E‐Hy‐CI) is a generalization of the Hylleraas‐configuration interaction (Hy‐CI) in which the single of an Hy‐CI wave function is generalized to the generic type . This type of correlation has the right behavior both in the vicinity of the cusp and as goes to infinity; this work shows that wave functions containing both linear and exponential factors converge more rapidly than either one alone for low‐lying excited states of 1S symmetry. E‐Hy‐CI variational calculations with up to 8568 configurations lead to a nonrelativistic energy of −7.2799 1341 2669 3059 6491 6759 hartree for the 1 1S ground state of the Li+ ion.