CONTRIBUTIONS TO MULTIPHONON TRANSITION THEORY

Certain contributions to the multiphonon transition theory are reviewed. The topics reviewed include: i) some theoretical work directed towards clearing up certain long standing muddles in the historical development of the nonradiative transition theory; ii) the concept of multi-frequency model and the method of steepest method as the appropriate method for its implementation; iii) statistical frequency distribution law for phonons emitted in a multiphonon transition.