Fig. 4.

Numerical simulation of the DNA model in contact with a thermal bath at 270 K. The stretching of the base pairs is shown by a gray scale going from white for a closed pair to black for a fully open pair (y ≥ 2.0 Å). The vertical axis extends along the DNA chain, which has 256 base pairs in this calculation, with periodic boundary conditions. The horizontal axis corresponds to time. The time domain shown in this figure is 2 × 10^− 11 s. The parameters used for this calculation are m = 300 atomic mass units, D = 0.05254 eV, α = 4.0 Å^− 1, K = 0.01 eV Å^− 2, ρ = 3.0, δ = 0.8 Å^− 1