Molecular dynamics study of hydrogen diffusion in the C2 Hydrogen Hydrates

Abstract

Abstract We performed molecular dynamics calculation to study hydrogen molecules’ diffusion in the voids of C2 hydrogen hydrate with varied occupancy at 291K and 4GPa. The same hydrate systems under pressure conditions of 76MPa to 174.2MPa at 77K to 150K were also investigated. LAMMPS molecular dynamics program is employed to the 3×3×3 unit cells with periodic boundary conditions of C2 hydrogen hydrate. TIP4P/Ice and three sites were used to model water molecules and the encapsulated hydrogen gas, respectively. The whole system was simulated for 10ns. The diffusion coefficient calculations show conformity with the experimental results, with the highest of 9.07 × 10−9 cm2s−1 shown by a system of 80% hydrogen gas occupancy under 291K and 4GPa of temperature and pressure, respectively. Hydrogen gases are actively diffuse between voids in every simulated system configuration.