Experimental testing of molecular dynamic functions of pairs by the isotope selectivity of radical recombination

A method for experimental testing of the molecular dynamic function f(t), which describes the generation of reencounters in a dynamic pair of molecular particles, has been developed. The method is based on the analysis of isotope separation in spin selective reactions of a radical pair. The f(t) function derived from the solution of the diffusion equation with physically rigorous initial and boundary conditions describes experimental results much better than the well-known Noyes function. Conditions that make it possible to increase the efficiency of isotope separation in spin selective reactions are formulated.