Theoretical 14N nuclear quadrupole coupling surface for ammonia

Abstract

A property surface has been calculated by SCF theory for the variation with symmetric stretch and inversion motions of the electric-field gradient at the nitrogen centre in ammonia. The SCF calculations in a polarised basis overestimate the value of q_zz in the ground state of ¹⁴NH₃ by 9%. On introduction of a single scaling factor, vibrational averaging using empirical non-rigid-invertor wavefunctions gives satisfactory reproduction of experimental data for low vibrational states of symmetric isotopomers.