Microheterogeneity in mixtures of benzene with alcohols and hydrocarbons: Positron annihilation and molecular light scattering

Experimentally measured concentration dependences of the probability of positronium formation and the intensity of molecular light scattering in binary benzene-ethanol and benzene-cyclohexane mixtures were analyzed. The observed behavior was explained by association of molecules. Arguments are presented in favor of the formation in benzene-ethanol mixtures of alcohol associates capable of capturing and solvating quasi-free electrons formed in the tracks of high-energy positrons during their passage through the mixture. As the concentration of associates rises, the positronium formation rate decreases while the intensity of the light scattered by them increases. The mean size and lifetime of the associates were evaluated. It was established that, in benzene-ethanol and benzene-cyclohexane mixtures at temperatures below room temperature, benzene associates are formed.