报告题目：Pressure collapsed ice and clathrate hydrates and the model of two liquid water phases

报 告 人： Ove Andersson, associate professor

Umeå University, Sweden

摘要： Water is the most ubiquitous solvent and has unique structural and physicochemical properties. But our understanding of water’s structure - property relationships is amazingly weak and highly debated. Recently it has been suggested that the water structure is inhomogeneous and that ambient water structure is a mixture of nanometer-sized patches of tetrahedral-like, low-density liquid (LDL), and hydrogen-bond distorted, high-density liquid (HDL), structures, which coexist in a temperature pressure (T,p) -dependent equilibrium where high p,T promotes HDL and low p,Tfavours LDL. This extraordinary finding may completely change our view of the water microstructure and provide a universal explanation of water’s unusual physical properties in terms of a gradual HDL-LDL transformation. The model originates from the discovery of two distinct amorphous solid ice phases at low temperatures: HDA and LDA, via pressure induced amorphization. The key to investigate this controversial model’s relevance in explaining water’s properties is found at high pressures and in the domains of extreme, supercooled, water. In this range, the model implies a first-order transition line between, two liquid phases, HDL and LDL, which ends in a (second) critical point. Thus, a big step towards verifying the model is to prove that HDA and LDA transform into liquid phases on heating. We have studied this issue both in water and clathrate hydrates and found results that indicate a glass-liquid transition in HDA.

报告人简介：Ove Andersson, associate professor at Umeå University, Sweden, focuses on, in-situ, high pressure studies of hydrogen bonded liquids and polymers. Main methods include thermal conductivity, heat capacity and dielectric measurements.

地点：前卫南区唐敖庆楼C区603报告厅

时间：2016年5月18日（周三）上午10:00

举办单位：超硬材料国家重点实验室

物理学院

尊龙凯时省物理学会

中国物理学会高压物理专业委员会