ORIENTATIONAL CORRELATION-FUNCTIONS AND POLARIZATION SELECTIVITY FOR NONLINEAR SPECTROSCOPY OF ISOTROPIC MEDIA .2. 5TH ORDER

The influence of orientational relaxation on the fifth-order nonlinear polarization is evaluated for off-resonant Raman and dipole resonant experiments in the perturbative limit. The symmetry properties of the chi((5)) tensor are discussed, and correlation functions for orientati onal diffusion are calculated for all fifth-order tensor elements rele vant to isotropic media. The results allow generalization of the effec t of orientational motion on the nonlinear experiment of arbitrary ord er. The general polarization dependence of the fifth-order experiments are obtained and used to address the selectivity of certain polarizat ion geometries to orientational dynamics. It is shown that for chi((5) ) Raman spectroscopies, no combination of polarizations will give comp lete selectivity to the isotropic, anisotropic, or nonresonant contrib utions to the Raman polarizability tenser. Similar restriction of sele ctivity exists for resonant experiments. Polarization conditions are s uggested to facilitate the comparison of third- and fifth-order spectr oscopies. (C) 1996 American Institute of Physics.