Fluctuation of the electronic coupling in DNA: Multistate versus two-state model

The electronic coupling of guanines G in (GT)6GTG(TG)6 is computed using a combined QC/MD scheme. The two-state scheme considerably underestimates the probability of HT in DMA. The probability distributions computed with the two- and four-state schemes are quite different. Big fluctuations, which are at least an order of magnitude larger than the average value of V2, occur roughly every 1 ps.