Research Interests

My research interests lie in the use of x-rays and electrons for probing the structure of solids, liquids, surfaces, and interfaces. Specifically, I am interested in using x-ray absorption spectroscopy and x-ray scattering to study the structure of solid-solid and solid-liquid interfaces, random semiconductor alloys, two-dimensional phase transitions at surfaces and interfaces, the structure of liquids, and biological and environmental problems. My personal interests largely involve fundamental problems in condensed-matter physics, but our research is deeply involved in interdisciplinary studies of environmental geochemistry, nanoparticle/nanowire structure and function, catalysis, metallochemistry, and other areas.

This research largely requires the use of very intense x-rays available only at national synchrotron-radiation sources. To this end, I have been very active with two research groups for the construction and operation of beamlines at the National Synchrotron Light Source. I am also the Director of a collaboration that has built and now operates two beamlines at the Advanced Photon Source, the only high-energy “Third Generation” x-ray synchrotron source in North America. This group, the “Materials Research Collaborative Access Team” (MRCAT) involves Notre Dame, Illinois Institute of Technology, Argonne National Laboratory, the US Environmental Protection Agency, UOP/Honeywell, and the BP Corporation. I am also past Chair of the International X-Ray Absorption Society, a user organization with over 1,100 members, and a Fellow of the American Physical Society.