Exchange spin polarization in a three-particle system

A theory of spin polarization in a system of three particles is developed. Each particle is assumed to possess a spin of 1/2. The total system is initially assumed to be in a prescribed spin state. Redistribution of the initial polarization occurs as a result of an exchange interaction during particle collisions. In particular, the beam of nonpolarized electrons scatter by orientated atoms becomes polarized to a certain extent. On the basis of the results obtained the polarization of the scattered beam and target in elastic and inelastic collisions, involving exchange of particles, can be calculated for arbitrary initial polarization states. Results are presented of numerical calculations of the polarization of electrons scattered by oriented He(23S) atoms and also of the depolarization of electrons caused by singlet-triplet transitions