Charge transfer in DNA: The role of large polarons

Abstract

Polaronic mechanism of charge transfer in DNA is considered on the basis of one-dimensional Su-Schrieffer-Heeger (SSH) model Hamiltonian. It is shown that usually used values of SSH model Hamiltonian parameters, especially transfer integral and electron-phonon coupling constant which are obtained in the framework of ab initio calculations, do not give reliable resolution of the problem of (large) polaron applicability for charge migration in DNA. Because of that, theoretical method is proposed which enables us to estimate explicitly electron-phonon coupling constant on the basis of transfer integral. The value of polaron width obtained for such determined parameters leads to the conclusion that coherent motion of large polaron represents dominant mechanism of charge transfer in DNA.