Using the exponential dependence, the DO at low temperatures were estimated, 4.5×10 -3 Å 2 /ns and 81.6 Å 2 /ns at 300 K and 900 K respectively. Considering a one-dimensional diffusion with distance of 6 Å, the diffusion time is 0.22 ns under 900 K, 0.92 ns under 700 K, 2.72 ns under 600 K, and 4007.96 ns under 300 K.