Career
He is the Roger B. Bost Distinguished Professor of Chemistry in the Department of Chemistry and Biochemistry at the University of Arkansas, United States.
His most important contribution is the introduction of the gradient method in quantum chemistry. This allows the prediction of the geometric structure of a molecule using computational chemical programs to be almost routine. He is the main author of the PQS computational chemistry program
His work was cited in the official background material for the 1998 Nobel Prize in chemistry.