<i>Ab initio</i> MO studies of nuclear spin-spin interactions in NH<img src='http://www.niscair.res.in/jinfo/two.gif' border=0>, NH₃, NH<img src='http://www.niscair.res.in/jinfo/plusfour.gif' border=0> and N₂H₄

Abstract

Indirect spin-spin coupling constants in NH<img src='http://www.niscair.res.in/jinfo/two.gif' border=0>, NH₃, NH<img src='http://www.niscair.res.in/jinfo/plusfour.gif' border=0> and N₂H₄ have been calculated employing the SCF perturbation theory at the ab initio level. For N the (10s6p) basis set of Dunning, which is contracted to [5<i>s</i>3<i>p</i>], has been used while the same author's (5<i>s</i>) basis set of H is contracted to [3<i>s</i>]. In all the calculations basis sets have been augmented with bond centred functions, or nuclear centred higher angular momentum functions, or both. In addition, the consequence of decontraction of basis sets, particularly <i>s</i> functions, is tested. For all practical purposes, a basis set containing bond functions along with uncontracted innermost <i>s</i> function yields good results. For the vicinal couplings, the basis set need not necessarily be large as these couplings are insensitive to the size of the basis set.