Effect of structural transformations in a crystal-matrix on superradiance evolution

The effect of structural transformations in the crystal-matrix of diphenyl on the parameters of the radiation emitted by impurity diphenyl molecules in 1B2u→1A8 (SR) and 1B2u→1Ag×ag transitions has been investigated experimentally in the temperature range from 1.5 to 60° K. The results obtained are interpreted on the assumption that superradiance is emitted in the 1B2u→1Ag×ag transition, which is complicated by radiation relaxation from the 1Ag×ag sublevel.