Semiempirical Calculations of Some 2H and 14N Nuclear Quadrupole Coupling Constants

Abstract

A parameterized LCAO method for the calculation of nuclear field gradients is described. The principal difference between this and other theories concerns the treatment of the two‐center contribution to the field gradient. In our method, the two‐center terms are included as parameters proportional to their respective nuclear terms. Only three parameters are necessary, one for triple and double bonds, one for single bonds, and one for a bond to hydrogen. The method developed herein not only successfully reproduces ¹⁴N field gradients, but also ²H field gradients, heretofore not possible with other semiempirical methods.