This award will facilitate continued collaboration between physicists at Kansas State University and Argonne National Laboratory in the U.S. and the University of Electro- Communications, the University of Tsukuba, and Kyoto University in Japan. The scientists are cooperating in a study of what are known as electron correlation effects in heavy particle collisions and in collisions of atoms with antimatter. These effects arise when the processes being observed depend on the interaction between two or more electrons. Such interaction or interdependency in general requires a much more complicated and difficult treatment than when one-electron processes are considered. Examples of two-electron processes are double capture, transfer excitation, transfer ionization, double ionization, and double excitation. These phenomena are of current experimental interest, and they pose new challenges to theorists. The principal investigators in this project under the U.S.-Japan Cooperative Science Program are Dr. James H. McGuire, Kansas State University, and Dr. Michio Matsuzawa, The University of Electro-Communications, Tokyo, Japan. The collaborating researchers in this current activity will examine the impact excitation of doubly excited states and double ionization of helium atoms by protons and antiprotons over a wide range of collision energies. They will also study some aspects of Coulombic three-body systems by analyzing the wave functions in the body-frame of the system, using mass- weighted hyperspherical coordinates. The U.S. and Japanese groups have been investigating similar topics and have collaborated previously. Exchanging and combining methods and computer codes should prove beneficial to each group involved, and to the understanding of the physical processes being studied.
