Spectra and transport of self-trapped excitons

The physics of exciton ST has many features in common with electron (hole) ST. Therefore, the methods and results of the theory of electron ST have been widely used in the development of the theory of exciton ST. The effects of strong exciton-phonon coupling in organic crystals and the possibility of exciton ST were discussed in the papers by Peierls (35), Frenkel (36), and Davydov (37). 

More recent discussion of exciton ST and the synthesis of almost all available approaches may be found in the reviews published as Refs. (32), (38)-(40). The reader is referred to this literature for a detailed account of exciton ST. In the following subsections, we will restrict ourselves to a qualitative description of the most general and characteristic features of this phenomenon. 

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