EXCITED STATE SELF-CONSISTENT FIELD THEORY USING EVEN-TEMPERED PRIMITIVE GAUSSIAN BASIS SETS

A practical Hartree-Fock theory of atomic and molecular electronic structure is developed for individual electronically excited states that does not involve off-diagonal Lagrange multipliers. An easily implemented method for taking the orthogonality constraints into account, which has been proposed earlier by one of us, is used to impose the orthogonality of the Hartree-Fock excited state wave function of interest to states of lower energy. The applicability of systematic sequence of even-tempered basis sets with the orbital exponents, ζp, defined by the geometric series ζp = aβp is examined in Hartree-Fock energy calculations for excited states which have the same spatial and spin symmetry as the ground state. It is shown that a simple reoptimization of the a and β parameters leads to a sequence of even-tempered basis sets capable of supporting high accuracy for excited state energies of some simple atoms.