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Atomic Physics

Dr. Scott Whitfield conducts experimental research in atomic physics. This research is focused on the dynamics of the photoelectric effect for atoms (photoionization) in the gas phase. The photoelectric effect is one of the most fundamental examples of the interaction of light and matter, and was first explained by Albert Einstein in 1905. The reaction is very simple: a photon (a particle of light) is absorbed by an atom, and if it carries sufficient energy, an electron from the atom is ejected into space with a definite kinetic energy. This process is studied experimentally by analyzing the behavior of the electrons which are ejected after absorption of the photon. Experimentally one can determine not only the basic atomic structure of the atoms involved, but one can also probe basic aspects of the quantum-mechanical nature of the photoionization process. These experiments require photon wavelengths which are beyond visible radiation, namely ultraviolet and soft x rays. Sources for such radiation are not easy to come by, so the experiments are carried out a synchrotron radiation facility, the most convenient being the Synchrotron Radiation Center run by the University of Wisconsin-Madison in Stoughton WI, just south of Madison.