Effect of isotope substitution on the magnitude of nonequilibrium nuclear polarization in photolysis of acetone in methanol

Polarization of nuclei in both the products of the reactions and in the CHD₂OD proton without polarization in the CH₃OH protons is observed in irradiation of a solution of acetone in CD₃OD in the presence of CHD₂OD and CH₃OH. Polarization of the protons of the products is strongly dependent on the temperature of the solution and arises in radical pairs; polarization of the proton of partially deuterated methyl alcohol is due to a mechanism of optical nuclear polarization. It was hypothesized that the isotope effect is due to a difference in proton and electron relaxation and to a difference in the rates of cross-relaxation transitions.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2683–2687, December, 1989.