Field Effects and Symmetry

The molecular polarizabilities obtained in the last two sections are microscopic parameters that characterize an individual molecule. To relate them to the bulk or macroscopic parameters, namely, the susceptibihties and so forth, one 

The local field correction factors for linear susceptibility were discussed in Chapter 3. In the usual studies of local field correction factors for nonhnear susceptibilities, molecular correlations that characterize hquid crystals are not taken into account. With this gross approximation, the second and third-order nonhnear susceptibilities of an isotropic medium or a meditrm with cubic symmetry containing N molecules per unit volume are given by  

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