Diffusion of nitrogen gas in ice Ih

Diffusion of N2 in ice crystal has been found from Raman scattering of the natural ice from the Antarctic ice sheet. In order to investigate the diffusion mechanism, we perform molecular dynamics simulations of diffusion of N2 in ice. The results show that the N2 molecule hops in the crystal by breaking hydrogen bonds in the ice lattice. The diffusion velocity with the mechanism is few orders larger than the estimate under the assumption of the interstitial mechanism. We conclude that the localized vibrational motion of N2 is the dominant factor governing the diffusion mechanism.