Charge transfer, symmetry, and dissipation in donor-acceptor molecules

We study charge transfer between donor-acceptor molecules subject to a mirror symmetry constraint in the presence of a dissipative environment. The symmetry requirement leads to the breakdown of the standard single reaction coordinate description, and to a new charge transfer model, in the limit of low temperature, based on two independent reaction coordinates of equal relevance. We discuss implications of these results to charge transfer between DNA base pairs, whose geometrical configuration is modified by the addition of the migrating charge in conformity with the discussed symmetry constraint.