Excitation transfer and internal conversion - Forster, T. (Elsevier)
The transfer of electronic excitation energy between separated chromophores is treated as an internal conversion process within the combined system. Quenching by transfer to vibrations of the acceptor chromophore appears as a subcase. The non-Born-Oppenheimer character of the compound state is essential for that kind of transfer.
http://linkinghub.elsevier.com/retrieve/pii/0009-2614(71)85102-3
Keywords: V; U