Dissociative electron transfer reaction definition

Primary process" has been used in accordance with this recently suggested definition (2) "Any continuous sequence of one or more primary steps which starts with the light absorption step." In this sense a primary step is "any one of the elementary transformations of an excited state molecule of the species which absorbs light. The absorption step Itself is also a primary step" (2). Important primary processes of OTM compounds which are described here include (1) absorption, (ii) dissociative reactions, (iii) intramolecular "twisting" isomerizations, (iv) intermolecular energy transfer, (v) inter-molecular electron transfer, (vi) luminescence. Reactions involving OTM compounds as quenchers have also been included. 

Coenzyme in the narrow sense, the dissociable, low-molecular-mass active group of an enzyme which transfers chemical groups (see Group transfer) or hydrogen or electrons. C. in this sense couple two otherwise independent reactions, and can thus be regarded as transport metabolites. In a wider sense, a C. can be regarded as any catalytically active, low-molecular-mass component of an enzyme. This definition includes C. that are covalently bound to enzymes as prosthetic groups. A holoenzyme consists of a C. in combination with an apoenzyme (enzyme protein). 

---