Disorder effects in dimerized bridged molecular systems

We discuss a model for transport properties in a donor-acceptor system conn ected by a dimerized chain. The system is assumed to be subject to site-dia gonal disorder. The average spectral properties of the system are discussed by using the random matrix Wegner model (Anderson's type tight-binding Ham iltonian (TBH)) for the electronic part of the problem. In our analysis we use the "Blue's function" (functional inverse of the resolvent) formalism. For a simple one-dimensional tight-binding picture, we show that the diagon al disorder destroys the energy gap emerging as a Peierls effect in a nonpe rturbed system without disorder, rederiving thus the results obtained earli er using different models of site randomness.