Temperature dependence of electron spinhyphen;lattice relaxation of methyl radicals in glassy organic matrices:Relation to environmental dynamics and radical decay

摘要

The electron spinhyphen;lattice relaxation of trapped methyl radicals in methanol , 2minus;methyltetrahydrofuran, and 3minus;methylhexane glasses has been directly studied as a function of temperature from 5hyphen;100 K by the saturation recovery method. The relaxation rate remains fast at low temperatures and shows a large component linear in temperature. This is interpreted in terms of the recently developed model of tunneling relaxation involving modulation of the electron nuclear dipolar interaction by tunneling of nuclei in the radicalrsquo;s environment lsqb;J.Phys.Chem.81,456 (1977)rsqb;. Deuteration experiments show that CH3and lsqb;J.Phys.Chem.81,456 (1977)rsqb;. Deuteration experiments show that CH3and CD3have the same relaxation rate while it is decreased by about fourminus;fold by deuterating the matrix. There also appears to be a correlation between the spinhyphen;lattice relaxation rate and the decay of methyl radicals in these matrices.