Excited states of the of the double-stranded DNA model (A)12⋅(T)_{12} were calculated in the framework of the exciton theory. The off-diagonal elements of the exciton matrix were calculated using the transition densities and ideal dipole approximation associated with the lowest energy ππ∗ excitations of the individual nucleobases obtained from TDDFT calculations. The values of the coupling calculated with the transition density cubes (TDC) and ideal-dipole approximation (IDA) methods were found significantly different for the small inter-chromophore distances. It was shown that the IDA overestimates the coupling significantly. The effects of the structural fluctuations were incorporated by averaging the properties of the excited states over a large number of conformations obtained from the MD simulations.
@article{arxiv.0708.1128,
title = {Calculations of the Exciton Coupling Elements Between the DNA Bases Using the Transition Density Cube Method},
author = {Arkadiusz Czader and Eric R. Bittner},
journal= {arXiv preprint arXiv:0708.1128},
year = {2009}
}