On the relevance of self-trapping as the mechanism for charge and energy transfer In biological systems

Abstract

The concept that polarons and solitons may play a crucial role as the underlying transport agents in biological structures has been critically 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 values of the basic physical parameters of the system, were formulated. It was found that Davydovs soliton model cannot explain the intramolecular energy transfer in the alpha-helix and acetanilide, and an alternative formulation in terms of the so-called Takeno model is more realistic. However, Davydovs theory is sufficiently flexible to describe electron transfer in the alpha-helix and acetanilide.