Microwave field effects on the time dependence of recombination fluorescence from non-polar solutions

A novel experimental setup to study the effect of microwave field on the ki netics of recombination fluorescence from nonpolar solutions irradiated wit h nanosecond X-ray pulses is described. Experiments on the observation of t he microwave field effects in dodecane and hexane solutions are presented. The most favorable conditions for observation of the microwave induced quan tum oscillations are found. The effect of spin locking was observed for the first time in the time-resolved microwave field effects, An efficient meth od to calculate the spin evolution of a radical pair in a microwave field t aking into account relaxation is suggested. Analytical expressions for the microwave field effect in the limiting cases of large and small hyperfine s plittings are given. (C) 1999 Elsevier Science B.V. All rights reserved.