Electron Spin Echo Study of the Steric Characteristics of the Formation and Reactions of Radicals in a Solid Phase

The general characteristics of electron spin echo (ESE) spectrometers are considered. A Soviet spectrometer and certain foreign instruments used in physicochemical research are described. The fundamental postulates and results of the theory of magnetic dipole–dipole interactions are briefly formulated in relation to the analysis of the results obtained by the ESE method. Studies by the ESE method of the steric characteristics of chemical reactions in solids are surveyed. Investigations of the structures of radical tracks in irradiated organic and inorganic systems are considered and it is shown that data concerning the pair distribution function with respect to distances in ion — radical pairs can be obtained by the relaxation probe method and the method of double electron–electron resonance in ESE spectroscopy. The principal results of the investigation of the pair distribution in the formation of radicals under the influence of ultraviolet light and γ-rays as well as the changes in the pair distribution in the course of diffusion and reactions of free radicals and atoms in frozen glasses are discussed. The bibliography includes 64 references.