Kerr relaxation of anisotropic dielectric particles and Neel relaxation ofanisotropic magnetic particles after a sudden change of field

Kerr relaxation of anisotropic dielectric particles and Neel relaxation of anisotropic magnetic particles after a sudden change of electric or magneti c field are studied on the basis of the Smoluchowski equation for the orien tation distribution function. The equilibrium average of a Legendre moment of any order is evaluated. The time dependence of the relaxation of polariz ation (first-order Legendre moment) and order parameter (second-order Legen dre moment) after a sudden change of field is determined by a fast and accu rate numerical method. (C) 2001 American Institute of Physics.