A superexchange-mediated sequential hopping theory for charge transfer in DNA

A formulation that readily allows quantitative comparisons with experimenta l chemical yields in long-range charge transfer in DNA is developed. The th eory is based on a superexchange-mediated sequential hopping model that tak es into account the multistep charge migrations (hopping) among guanine bas es and the individual substep of superexchange (tunneling) through adenines and/or thymines. An exact Ohm's law is established for kinetic multistep h opping processes, while the scattering matrix technique is exploited to det ermine the coherent unistep contributions. Presented are also the quantitat ive comparisons with the experimental measurements in some DNA molecules in volving intrastrand and/or interstrand charge transfer processes in aqueous solution. The dependence of product yield on both the length and the seque nce of DNA is clearly demonstrated.