Localization Properties of Electronic States in Polaron Model of poly(dG)-poly(dC) and poly(dA)-poly(dT) DNA polymers

摘要

We numerically investigate localization properties of electronic states in a static model ofpoly(dG)-poly(dC) and poly(dA)-poly(dT) DNA polymers with realistic parameters obtained byquantum-chemical calculation. The randomness in the on-site energies caused by the electronphononcoupling are completely correlated to the off-diagonal parts. In the single electron model,the effect of the hydrogen-bond stretchings, the twist angles between the base pairs and the finitesystem size effects on the energy dependence of the localization length and on the Lyapunov exponentare given. The localization length is reduced by the influence of the fluctuations in the hydrogenbond stretchings. It is also shown that the helical twist angle affects the localization length in thepoly(dG)-poly(dC) DNA polymer more strongly than in the poly(dA)-poly(dT) one. Furthermore,we show resonance structures in the energy dependence of the localization length when the systemsize is relatively small.