Dynamics of the magnetic moment in a polarized Boltzmann gas allowing for dissipation

An equation is derived for the dynamics of the spin magnetic moment in a po larized Boltzmann gas allowing for spin loss processes. The general form of the T matrix for collisions between two spin 1/2 particles allowing for in elastic processes is used. It is shown that the rate of spin loss depends o n the degree of polarization of the gas. As a result, the damping of deviat ions of the magnetic moment from the average becomes anisotropic where the degree of anisotropy depends on the amplitude of the zero-angle scattering of atoms. (C) 2000 MAIK "Nauka/Interperiodica".