Molecular dynamics study of ice in/on kaolinite under extreme conditions

Okumura, Masahiko   ; Kobayashi, Keita 

Ice is a common substance in everyday life, but ice in extreme conditions has different physical properties from the ice we are familiar with. It is known that under high pressure, water molecules are trapped between the layers of kaolinite and that these water molecules assume an ice-like configuration by interacting with oxygen atoms in the kaolinite. However, the physical properties of this configuration remain unknown. In addition, Interstellar dust has a silicate core surrounded by amorphous ice, which is thought to play an important role in the formation of organic matter. However, its detailed physical properties are unknown. In this study, we applied machine-learning molecular dynamics to kaolinite interlayer ice and evaluated its physical properties. In addition, the process of amorphous ice formation was discussed using classical molecular dynamics simulations, in which the atomically flat surface of kaolinite is assumed as an idealized interstellar dust core surface.