Role of photoresponse of π electrons in light-driven DNA dissociations.

Abstract

The role of photoresponse of π electrons in light-driven DNA dissociations is theoretically studied. A new model combining the Peyrard-Bishop-Dauxois model and the charge ladder model is first proposed. Then the evolutions of π-electronic states and H-bond stretching in the light-driven DNA dissociations are studied. The results show that light irradiation will induce ultrafast charge redistribution among bases, leading to the precursory insulator-to-metallic transition. This electronic transition will assist DNA to dissociate. Effects of screened Coulomb interactions on dissociation dynamics is emphatically discussed. Finally, it is also found that light-driven DNA dissociation preferentially occurs in the adenine-thymine-rich region rather than the guanine-cytosine-rich region.