The Calculation of 14N Quadrupole Coupling Constants with Basis Sets of High Local Quality

Abstract

An appropriate basis set to obtain electric field gradients close to the Hartree-Fock limit is evaluated for the nitrogen nucleus. An empirical correction for the error due to the neglect of electron correlation is given for sp-, sp2 - and sp3-hybrized nitrogen. The results are used to predict the full quadrupole coupling tensor for a few molecules. A breakdown of the electric field gradient into contributions from the single orbitals leads to a model for the field gradient due to the π-system and a partial rationalization of the part due to the σ-system. The results are discussed in relation to a Townes and Dailey analysis.