U.S.-Japan Cooperative Science: Molecular Motions in Water

该奖项支持波士顿大学H.Eugene Stanley博士和日本名古屋大学Masaki Sasai教授之间为期三年的合作研究项目。研究人员将对水中的合作分子运动进行光谱研究。这项研究的目的是通过分析水分子的协同运动来获得水的热力学和动力学性质的统一观点。水有许多奇怪的性质，其中一些为理解水的行为提供了重要线索。其中一个显著特征是在低温下存在两种非晶相：低密度无定形冰(LDA)和高密度无定形冰(HDA)。为了获得具有足够大关联长度的系统的可靠信息，需要对大得多的系统进行MD模拟。利用快速多极子方法，对分子数高达10/6的体系进行分子动力学模拟，分析过冷区的热涨落。对各种形式的冰的亚稳相和非晶相进行了实验研究，并研究了它们之间的转变。该项目汇集了两个拥有互补专业知识和研究能力的实验室的努力。通过对实验数据、分子动力学模拟和统计力学模型的总结，研究水的相图。研究结果将有助于揭示水的奇异行为的物理基础。这项研究通过博士后和研究生的参与促进了国际人力资源的发展。通过思想和技术的交流，这个项目将扩大我们的基础知识基础，促进国际理解与合作。研究人员计划在科学期刊上发表研究结果，并在科学会议上报告研究结果。

0003685StanleyThis award supports a three-year collaborative research project between Dr. H. Eugene Stanley of Boston University and Professor Masaki Sasai of Nagoya University in Japan. The researchers will be undertaking a spectroscopic study of cooperative molecular motions in water. The aim of the research is to obtain a unified view of the thermodynamic and dynamic properties of water by analyzing the cooperative motions of water molecules. Water has many strange properties, some of which provide important clues for understanding its behavior. One such remarkable feature is the existence of two amorphous phases at low temperature; low-density amorphous ice (LDA) and high-density amorphous ice (HDA). In order to obtain reliable information on systems with sufficiently large correlation length, MD simulations of significantly larger systems are necessary. By using the Fast Multipole Method, the MD simulation of the system containing up to 10/6 molecules will be performed and the thermal fluctuation in the supercooled region will be analyzed. Metastable phases of various forms of ices and the amorphous phases will be experimentally examined and transformations among them will be investigated. The project brings together the efforts of two laboratories that have complementary expertise and research capabilities. By summarizing the data of experiments, MD simulations, and the statistical mechanical models, the phase diagram of water will be studied. Results of the research will help to reveal the physical basis of the singular behavior of water. This research advances international human resources through the participation of a postdoc and graduate students. Through the exchange of ideas and technology, this project will broaden our base of basic knowledge and promote international understanding and cooperation. The researchers plan to publish results of the research in scientific journals and report on the findings at scientific meetings.