Nonlinear Orientational Response of Permanent Dipoles in a Mean Field Potential to Alternating Fields

It is shown how the existing theory of the dynamic Kerr effect and nonlinear dielectric relaxation based on the noninertial Brownian rotation of noninteracting rigid dipolar particles may be generalized taking into account interparticle interactions using a mean field potential. The results (available in simple closed form) suggest that the frequency dependent nonlinear response provides a new method of measuring the Kramers escape rate (or in the analogous problem of magnetic relaxation of fine single domain ferromagnetic particles, the superparamagnetic relaxation time).