Basic Conceptions: Spin Exchange and Electron Transfer

Abstract

Spin electron interactions play crucial roles in diverse topics related to electron transfer, environmental and biological issues, respiration, photosynthesis, radical reactions and electron transfer. Biological electron transfer (ET) reactions are essential for the conversion of energy from food or sunlight into the universal energy currency, adenosine triphosphate. Interest to radical processes including oxidative stress, antioxidant activity, some pathology, aging, etc. is fuelled by the many promising applications in biomedicine and clinical medicine. This Chapter is organized as follows. The first two Sections provide a brief preliminary overview on basic conceptions and definitions and the primary quantum mechanical grounds regarding for readers who may be less familiar with the spin physics. In next two Sections, we have presented basic information about different types of spin exchange processes, namely, static direct exchange and super exchange in an encounter complex in solution. Classic theories of electron transfer by Marcus, Levich, Jortner and Zusman and recent progress in the area have been considered. The close interrelations between spin exchange and electron transfer have been emphasized.