U.S.-Germany Cooperative Research on the Correlation betweenthe Nonmetal to Metal Transition in Clusters and at Surfaces

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9300238 Plummer This award supports Professors E. Ward Plummer of the University of Tennessee, Peter Dowben of Syracuse University, and N. John DiNardo of Drexel University to collaborate in condensed matter physics with three German counterparts: Professor Klaus Rademann and Dr. Ourania Rademann of the University of Marburg and Dr. Eckart Ruhl of the Free University of Berlin. The purpose of their cooperative research is to develop a picture of the fundamental mechanisms for the nonmetal to metal transition in the simple metals. The collaborative plan brings together three U.S. experimentalists who have done substantial research on the nonmetal transition in two dimensions and at solid surfaces to work with three German experimentalists who have done complementary research on the transition in clusters. The research requires substantial experimental work at a synchrotron light source, as well as access to other very specialized analytical equipment. The German collaborators are able to provide access to the German facility known as BESSY, in Berlin, while the U.S. collaborators will arrange for joint work at the U.S. National Synchrotron Light Source and other U.S. facilities suitable for the very complicated characterizations of alkali metal in surface islands and surface aggregates. Both U.S. and German postdoctoral associates and graduate students will be involved in the collaborative research. Transition metal clusters and aggregates exhibit a nonmetal to metal transition with increasing cluster size. Similar transitions have been observed for transition metal layers on solid surfaces. So far, the in-depth study needed to demonstrate a direct connection between metal to nonmetal transition in clusters and at surfaces has been done successfully only for one metal, mercury. These investigators propose to expand that base of knowledge by undertaking the necessary comparative research on transition in alkali metals. Since data already exist on alkali b ehavior in surface layers, the joint research will focus principally on the transition in clusters. Results from this research will contribute to understanding the basis for the difference in behavior between metals and non-metals. ***