Radical polarization in double switching of external magnetic field

Theoretical treatment of radical spin evolution under the action of double switching of external magnetic field is proposed. Account is taken of evolu tion of the radical spin state during laser pulse which generates paramagne tic particles. It is shown that the most effective beats in the nuclear mag netization of diamagnetic products of recombination occur upon the jump int o zero magnetic field after laser pulse. The phase of observed beats bears information about the type of the initial radical polarization. The frequen cy of the beats is determined by radical hyperfine structure. (C) 1999 Else vier Science B.V. All rights reserved.