Migration Paths of Helium in α-Quartz and Vitreous Silica from Molecular Dynamics Data

Abstract

The helium diffusion in α-quartz and vitreous silica is studied by the molecular dynamics method. It is shown that, as the temperature increases, the motion of a helium atom in crystalline quartz changes over from vibratory motion about the equilibrium position at 300 K to free displacements throughout the bulk of the crystal at 750 K. The helium diffusion in α-quartz and vitreous silica is described. It is demonstrated that even an insignificant number of structural defects increases the helium mobility.