Ab initio quadratic configuration interaction calculation of indirect NMR spin-spin coupling constants

Abstract

Finite-field perturbation theory is combined with the quadratic configuration interaction method of ab initio electronic structure theory to calculate the Fermi-contact component of the indirect spin-spin coupling constant between adjacent carbon nuclei in a range of bonding environments. Basis set requirements for accuracy are first investigated in ethane and a small modification of the outer-core, inner-valence region of the standard Dunning double-ζ contraction is shown to be satisfactory