He joined the faculty at the University of Illinois at Urbana-Champaign in 1981, where he devoted his career to the spectroscopic analysis of intermolecular interactions in neutral and charged molecular clusters. In 2011, after spending nine months at Ruhr University Bochum, he joined the National Science Foundation in Arlington, Virginia as a program officer, a position he held for the next five years. Since then he has participated in the Tokyo Tech World Research Hub Initiative, which fosters interdisciplinary exchange between the world’s top researchers.