Experimental studies of molecular kinetics, structure, and thermodynamic properties of pure and doped amorphous solid water at temperatures above 160 K

在化学系化学结构、动力学和机制项目的支持下，乔治华盛顿大学的Vladislav Sadtchenko教授和他的研究生和本科生正在使用量热、光学和质谱技术研究深度过冷水和水溶液的结构和动力学。这种新颖的实验方法依赖于在低温下快速加热在衬底上气相沉积的纯和掺杂非晶固体水膜。在这种实验中采用的快速加热使水膜的明显结晶成为可能，从而可以在所谓的“无人区”温度范围内研究水，即缺乏水的性质数据。本研究的主要目标是：1)通过提供水在以前无法达到的温度范围内的性质的实验数据，促进对水的热力学和分子动力学的全面基本描述的发展；2)在各种水合化学物质存在下对水的分子动力学和结构的深入了解；3)调和过去对过冷水的经常相互矛盾的实验研究结果。由于水在自然界中无处不在，它在众多环境、生物和工业过程中发挥着重要作用，这些研究的结果将对各种各样的科学应用领域产生影响。研究活动对科学方法的进步也很重要。快速扫描量热技术在其他（非水）体系研究中的潜在应用有很多，可能包括聚合物和其他具有商业意义的材料中的弛豫现象的研究。拟议的研究活动将通过为一名研究生（博士）和几名本科生提供研究培训，促进美国的人才发展。这项工作的更广泛影响也将通过在大华盛顿地区的公共推广计划来实现。

In this project supported by the Chemical Structure, Dynamics and Mechanisms Program of the Division of Chemistry, Professor Vladislav Sadtchenko of the George Washington University and his graduate and undergraduate students are investigating the structure and dynamics of deeply supercooled water and aqueous solutions using calorimetric, optical and mass spectroscopic techniques. The novel experimental approach relies on rapid heating of pure and doped amorphous solid water films vapor-deposited on a substrate at cryogenic temperatures. The rapid heating employed in such experiments makes it possible to avoid significant crystallization of the aqueous films and thus to study water in so-called "No Man's Land" temperature range, i.e., where data on water's properties is lacking. The principle goals of the research are: 1) to facilitate development of a comprehensive fundamental description of thermodynamics and molecular kinetics of water by providing experimental data on it s properties in a previously inaccessible temperature range, 2) to gain insights into the molecular kinetics and structure of water in the presence of various hydrated chemical species, and 3) to reconcile often conflicting results of the past experimental studies of supercooled water. Due to the ubiquitous presence of water in nature and its role in a multitude of environmental, biological, and industrial processes, the result of these studies will have an impact on a great variety of applied fields of science. The research activities are also important for advancement of the scientific method. Potential application of the fast scanning calorimetry technique in research on other (non-aqueous) systems are numerous and may include studies of the relaxation phenomena in polymers and other commercially significant materials. The proposed research activities will contribute to personnel development in the US by providing research training of a graduate (Ph.D.) and several undergraduate students. The broader impact of the work will also be achieved through a public outreach program in the greater Washington DC area.