VIBRATIONAL VERSUS ELECTRONIC FIRST HYPERPOLARIZABILITIES OF MONOSUBSTITUTED AND DISUBSTITUTED BENZENES - AN AB-INITIO COUPLED HARTREE-FOCKINVESTIGATION

Static electronic and vibrational longitudinal first hyperpolarizabili ties (beta(L)(e)(0) and beta(L)(v)(0)) of a series of mono- and disubs tituted benzenes were calculated at the Hartree-Fock 6-31G level by us ing coupled Hartree-Fock and the double harmonic oscillator approximat ions, respectively. Although the beta(L)(v)(0)/beta(L)(e)(0) ratio is slightly larger than unity and rather constant with respect to the sub stituent(s), it turns out, for the monosubstituted compounds, that the variations of beta(L)(e)(0) upon substitution can be most accounted f or by the mesomeric effects, whereas for beta(L)(v)(0), the inductive effects are also of importance. (C) 1997 John Wiley & Sons, Inc.