Influence of weak magnetic fields on radical-pair reactions

The time dependences of the populations of radical-pair spin states and transition amplitudes between them have been calculated for constant and pulsed magnetic fields, with allowance for hyperfine interaction. The above-mentioned characteristics have been found directly by solving the Liouville equation for the radical-pair spin density matrix. It is established that the relaxation of spin-level partial populations oscillates with a monotonic decrease in the total population. Original Russian Text ? M.N. Levin, Yu.V. Ivankov, E.Yu. Ivankova, O.A. Ivanova, 2009, published in Izvestiya Rossiiskoi Akademii Nauk. Seriya Fizicheskaya, 2009, Vol. 73, No. 2, pp. 249–252.