 He also worked on the faculty of State University of New York, Plattsburgh and State University of New York, Buffalo before joining the faculty at the University of Delaware in 1981.He left Delaware in 2003 and joined the faculty at the University of California, San Diego.Rheingold's fields of expertise and research interest are main-group and transition-metal organometallic chemistry, gas-phase cluster synthesis, thermoelectric materials and single-crystal structural determinations.