R. Stephen Berry (born 1931 in Denver, Colorado) is a U.S. professor of physical chemistry.
He is the James Franck Distinguished Service Professor Emeritus at The University of Chicago and Special Advisor to the Director for National Security, at Argonne National Laboratory. He joined the Chicago faculty in 1964, having been an Assistant Professor at Yale University and, between 1957 and 1960, an Instructor at the University of Michigan. At the University of Chicago, he has been a member of the Department of Chemistry, the James Franck Institute, the College, and, for many years, the Committee and then the School of Public Policy Studies.
He was Home Secretary of the National Academy of Sciences from 1999 until 2003. He has written one book, been co-author of four others, one with Stuart A. Rice and John Ross, another with Linda Gaines and Thomas V. Long, another with Vladimir Kazakov, Stanislaw Sieniutycz, Zbigniew Szwast, and Anatoly Tsirlin, and one with Boris Smirnov. He has also been author or coauthor of approximately 500 papers, mostly scientific.
His scientific studies have included both experimental and theoretical work. His doctoral thesis, directed by William Moffitt, was on the subject of the electonic structure of butadiene. He then went on to study alkali halides in the gas phase, and, first at the University of Michigan and then at Yale, used shock waves to produce sufficient dissociation of the molecules to ions to make it feasible to observe the photodetachment spectra of the halide ions, thus determining the electron affinities of the halogen atoms to four or five significant figures. He worked at Michigan with Martin Stiles to observe free benzyne in the gas phase, and then, at Yale, with a graduate student Margaret Emery and an undergraduate John Clardy, found the meta and para isomers of benzyne. He also worked with Walter Lwowski to study nitrenes in the gas phase. In 1964, he moved to The University of Chicago, where he has worked on atomic and ionic collision processes, photoionization, the nature of correlation of valence electrons in atoms, and, more recently, on atomic and molecular clusters, and on protein dynamics. He became interested in energy and its efficient use first through concern about Chicago's air pollution in the 1960's. This led to what we believe is the first public study of what has become called "life cycle analysis." This was an analysis of the actual and ideal limiting energy and free energy use in the manufacture and disposal of the automobile, and was carried out with Margaret F. Fels. This led to many other such analyses, which now are done very frequently. This work, in turn, stimulated what has become known as "finite-time thermodynamics," the study of the optimal performance of processes constrained to operate in finite time or at nonzero rates.
His interests, apart from traditional scientific studies, have included energy and energy policy (which he is currently teaching with the economist George Tolley), scientific integrity issues, scientific information, its distribution and its contributions to policy and governmental decisions including those of the courts, and science education, particularly the problem of science illiteracy.
He is married to Carla Friedman Berry. They have two daughters, Andrea and Denise, and a son Eric. All are married with children, a total of 8.
His current research focuses on the nature and topography of complex energy surfaces of clusters, nanoscale particles and proteins, and how the topography of a potential surface is related to the dynamics and kinetics of "moving about on that surface". In particular, one of the main issues is determining the topographical features that make the difference between a "glass-former" and a "structure-seeker".