• Senior Chemist and Photosynthesis Group Leader, Chemical Science and Engineering Division, 1995-present

• Chemist, Chemistry Division, Argonne National Laboratory, 1989-1995
• Assistant Chemist, Chemistry Division, Argonne National Laboratory, 1984-1989
• NSF Postdoctoral Fellow, Centre d'Etudes Nucleaires de Saclay, France, 1982-1984
• NIH Postdoctoral Research Fellow, Eastern Pennsylvania Research Institute, Philadelphia, Pennsylvania, 1980-1982
• Postdoctoral Research Fellow, Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, PA, 1979-1980
• Ph.D, Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, PA 1978

• Founding Member Argonne Northwestern Solar Energy Research (ANSER) Center
• Fellow American Association for the Advancement of Science (AAAS) (2006)
• Scientific Theme Leader, Bio-Inorganic Interface, Center for Nanoscale Materials, Argonne National Laboratory (2001-2007)
• Advanced Photon Source Program Review Panel (2003 -2006 )
• Intense Pulsed Neutron Source Proposal Review Panel (2002 -2007)
• Sector 12 Advisory Committee

Interests

• Photo-induced electron transfer and solar energy conversion in natural and artificial photosynthesis
• Bio-mimetic and supramolecular chemistries
• X-ray scattering for measurement of bio-and supramolecular structure and dynamics
• Time-resolved x-ray scattering