Sum-over-states calculation of the nuclear spin coupling constant of hydrogen fluoride

Abstract

The calculations of the spin-spin coupling constant of HF using extended-basis SCF orbitals which were made originally by Kato and Saika have been re-investigated. The calculated coupling constant is still found to be positive (836 hz) if the approximations introduced by Kato and Saika for the excited state energies are removed. Configuration interaction amongst the excited states does not significantly improve the convergence of the sum-over-state expression for J. It is shown that there should be an isotope effect on the reduced coupling constant which is largely determined by the anharmonic terms of the potential.