THEORETICAL INVESTIGATION OF THE KERR-EFFECT FOR CH4

The vibrational contributions to the Kerr effect and to electric-field -induced second-harmonic generation (ESHG) are calculated for methane for a number of optical frequencies. The latter results, together with the experimental ESHG values of the total mean second hyperpolarizabi lity, allow for the determination of the omega(L)(2)-dispersion curve for the mean electronic hyperpolarizability. Since this curve is ident ical, to fourth order, for both processes, we are able to combine it w ith the calculated Kerr vibrational hyperpolarizabilities and predict the total Kerr hyperpolarizabilities for CH4 for several laser frequen cies. (C) 1995 American Institute of Physics.