Theoretical prediction of new ice polymophs and their phase behaviors

2015 Fiscal Year Final Research Report

• Project/Area Number: 25288008
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Partial Multi-year Fund
• Section: 一般
• Research Field: Physical chemistry
• Research Institution: Okayama University
• Principal Investigator: Tanaka Hideki 岡山大学, 自然科学研究科, 教授 (80197459)
• Co-Investigator(Kenkyū-buntansha): MATSUMOTO Masakazu 岡山大学, 大学院自然科学研究科, 准教授 (10283459)
• Project Period (FY): 2013-04-01 – 2016-03-31
• Keywords: 水 / 氷 / ハイドレート / シミュレーション / 高圧

Outline of Final Research Achievements

We have calculated various thermal properties of ices including ice XVI such as the negative thermal expansivity. It is also found a possible mechanism for contraction of ice upon accommodation of guest spaces and disappearance of the negative thermal expansivity. Large scale molecular dynamics simulations, which are much closer to laboratory conditions, have been performed to investigate a dissociation mechanism of methane clathrate hydrate. A large and a long time molecular dynamics simulation reveals that a plastic phase of water transforms to ice VII via second order phase transition in high temperature and pressure condition, whereby a critical line replaces the usual phase boundary of first order.

Free Research Field

化学