Carbon-proton and proton-proton spin-spin coupling surfaces for the methane molecule

Abstract
Carbon-proton 1 J and proton-proton 2 J spin-spin coupling surfaces for the methane molecule have been calculated using a Hartree-Fock wavefunction. The dependences of all four contributions—Fermi contact, spin-dipolar, orbital paramagnetic and orbital diamagnetic—upon a set of four internal symmetry coordinates are presented. All first order derivatives and many of the second order derivatives of both surfaces have been obtained. The principal feature of the results is the very great dependence of the magnitudes (and often the signs) of the contributions upon the molecular geometry.