ON THE RELEVANCE OF SELF-TRAPPING AS THE MECHANISM FOR CHARGE AND ENERGY-TRANSFER IN BIOLOGICAL-SYSTEMS

The concept that polarons and solitons may play a crucial role as the underlying transport agents in biological structures has been critical ly re-examined on the basis of the general theory of self-trapping (ST ) phenomena. The conditions determining the existence and stability of polarons and solitons, and their character as a function of the value s of the basic physical parameters of the system, were formulated. It was found that Davydov's soliton model cannot explain the intramolecul ar energy transfer in the alpha-helix and acetanilide, and an alternat ive formulation in terms of the so-called Takeno model is more realist ic. However, Davydov's theory is sufficiently flexible to describe ele ctron transfer in the alpha-helix and acetanilide.