Theoretical Study on the chiral order in liquid water

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K05658
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Physical chemistry
• Research Institution: Okayama University
• Principal Investigator: MATSUMOTO Masakazu 岡山大学, 異分野基礎科学研究所, 准教授 (10283459)
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: 水 / 構造 / シミュレーション / 分子動力学 / 氷 / 相図 / キラリティ / 極限環境の水

Outline of Final Research Achievements

A new order parameter is proposed to distinguish the structures of water at room temperature, supercooled water and several types of ice at the molecular level. Using this technique, the process of ordering supercooled water into ice can be visualized. Molecular dynamics simulations were performed under high pressure to discover that at least two new ice crystals are spontaneously formed and to develop a method to identify their structures. The phase diagram of ice at negative pressure has been proposed, but we have made a deeper consideration of it, investigated an unprecedented number of crystal structures, and proposed a more realistic phase diagram of negative pressure. For the simulation, software for easily making crystal structure of all ice was made and was opened to public free of charge.

Free Research Field

理論物理化学

Academic Significance and Societal Importance of the Research Achievements

太陽系には極低温・真空から超高温高圧までさまざまな環境の氷が存在し、天体の物理的性質に大きな影響を与えている。我々のこの3年間の研究では、非常に幅広い温度・圧力範囲での氷の性質を理論的に予測し、これまでの未解決問題をいくつも解決に導いた。また、シミュレーションや解析を助けるさまざまなソフトウェアや解析指標を提案し、この研究分野の研究の発展に寄与した。