Molecular dynamics simulation for the formation of argon clathrate-hydrate structure

Investigation of argon clathrate-hydrate formation using molecular dynamics (MD) simulation has been conducted in order to clarify the mechanism of the growth of clathrate-hydrate complex structure. The calculation condition was that the motions of 360 H₂O molecules were given by the potential functions, while the positions of 64 argons (guest molecules) were fixed. After around 160 ps, the H₂O molecules formed a cagelike structure around the Ar molecules. It was revealed from the MD simulation that the short-range repulsive forces of argon molecules restrict the H₂O molecules' motions in a small range between the Ar molecules, which causes the H₂O molecules to be rearranged in five- and six-membered rings and to form a successive cagelike structure.