Study of polarization CRS and polarization ICRS with application to benzena

Passage from the microscopic third‐order optical polarizability tensor to the macroscopic third‐order susceptibility tensor elements in coherent Raman scattering (CRS: CARS and CSRS) is reviewed with appropriate orientation averaging for an isotropic medium. The results are applied to existing polarized CARS measurements for the 991 cm −1 vibration in benzene as a neat liquid [M. D. Levenson and N. Bloembergen, J. Chem. Phys. 60, 1323 (1974)] and also to new polarized interferometric data on the same system from a method called interferometric coherent Raman spectroscopy (ICRS; ICSRS in particular is used). Lineshape analysis of the CARS spectra seen in both the ZXXZ polarization (mildly dispersive) and the ZZZZ polarization (strongly dispersive) leads to ratios for the non‐resonant to resonant parts of the corresponding susceptibility elements. Thus X /X = 0.5 (from 0.3‐1.7) (a new result) and X /X = 0.042 + 0.002 (from Levenson and Bloembergen). It is shown that given one ratio, the second must be completely determined by the depolarization ratio from conventional Raman scattering. These same tensor element ratios are incorporated into ICSRS theory to produce polarized interferograms which qualitatively confirm the strikingly different patterns seen in the ZXXZ and ZZZZ polarized ICSRS experiments. On the quantitative level, agreement is less satisfactory.