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

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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.