Quantum chemical and molecular dynamics
modeling of charge transfer in DNA
The efficiency of charge transfer (CT) in DNA is determined by three key
parameters- the donor-acceptor electronic coupling, the CT driving force, and
the solvent reorganization energy.Computational approaches to estimating these
parameters are considered.
A new method, fragment charge difference scheme, for
estimating the electronic coupling is introduced. The method can be applied to
systems with several donor acceptor sites which are off resonance and shows a
high performance when treating the the electronic coupling in DNA. A combined
QM/MD method to calculate couplings is discussed.
Results of calculations on energetics of CT in DNA are presented.
Stabilization of the radical cation state localized on a base in 5'-XBY-3' is
shown to be essentially affected by the by subsequent base Y while the effect
of the preceding base X is small. A considerable influence of thermal
fluctuations of DNA environment on the CT energetics is found.
Calculational results on the reorganization energy and its dependence on
donor-acceptor distance, charge delocalization and structural fluctuations are