This award supports Dr. Mickey Gunter of the University of Idaho to collaborate in geological research with Dr. Thomas Armbruster of the Laboratory for Chemistry and Mineral Crystallography of the University of Bern, Switzerland. They share an interest in zeolites, a mineral group with unusual internal structure and valuable applications. Dr. Gunter's experience in mineralogy and zeolite chemistry is complemented by Dr. Armbruster's expertise in crystallography and the relationship of optical properties of minerals to their crystal chemistry. In addition, Dr. Armbruster's laboratory in Bern, where the joint work will be carried out, possesses state-of-the-art instruments and computers that are necessary for the proposed research. In 1990, Gunter and Armbruster performed crystal structure analysis on clinoptilolite, a mineral form of a zeolite, at five different hydration levels. Their current plans are to expand that work by measuring optical characteristics at various hydration levels. These data will help them to understand the effects of water on the optical properties of this mineral and to develop a simple method to correlate the properties to dehydration level. This will lay the groundwork for future optical studies on this mineral and other zeolites with different liquids occupying the channels. Zeolites are a large mineral group with an unusual structure comprised of channels in a framework. These channels give them commercially important uses as "molecular sieves," for applications such as water purification, petroleum refining, and radioactive waste treatment. For example, the subject of the proposed joint work, clinoptilolite, can absorb radioactive cesium and was used recently in the cleanup of Chernobyl. Very thorough characterization of zeolites will lead to a much better understanding of their crystal chemistry and physical properties and may make it possible to improve the "sieving" properties of these minerals.
