Chemistry at Illinois University of Illinois at Urbana-Champaign

Thom H. Dunning, Jr.

Director, National Center for
Supercomputing Applications;
Professor, Distinguished Chair for
Research Excellence in Chemistry

Professor Dunning received his B.S. in chemistry in 1965 from the University of Missouri–Rolla and his Ph.D. in chemistry/chemical physics from the California Institute of Technology in 1970. He was a post-doctoral fellow at both the California Institute of Technology and Battelle Memorial Institute. He took a position at Los Alamos National Laboratory in 1973, first in the Laser Theory Group and then in the Physical Chemistry Group. Dr Dunning was appointed group leader of the Theoretical and Computational Chemistry Group at Argonne National Laboratory in 1978. Beginning in 1989, Dr. Dunning held many positions at the Pacific Northwest National Laboratory, becoming director of the Environmental Molecular Sciences Laboratory in 1994 and the first Battelle Fellow in 1997. Dr. Dunning spent two years (1999-2001) in the Office of Science of the U.S. Department of Energy as Assistant Director for Scientific Simulation, where he was responsible for developing a new scientific computing program. Dr. Dunning then went to the University of North Carolina at Chapel Hill as a professor of chemistry and was responsible for supercomputing and networking for the University of North Carolina System. In 2002, he was appointed director of the Joint Institute for Computational Sciences, Distinguished Professor of chemistry and chemical engineering at the University of Tennessee, and Distinguished Scientist in computing and computational sciences at Oak Ridge National Laboratory. Professor Dunning joined the University of Illinois faculty in January, 2005.

Research

The research in my group is focused on (i) the development of techniques for the accurate solution of the electronic Schrödinger equation, and (ii) the use of state-of-the-art computational approaches to understand and predict the structure, energetics and reactivity of molecules.

Recent computational research has focused on the development of basis sets for calculations that include electron correlation. Correlation consistent basis sets, which systematically approach the complete basis set limit, have been developed for the main group atoms, B–Kr, plus hydrogen and helium. With these sets it is possible to dramatically reduce the error in the solution of the electronic Schrödinger equation. In fact, the dependence of many properties on basis set is so regular that it is often possible to extrapolate the results to the complete basis set limit. Atoms of current interest include the alkali and alkaline earth atoms as well as the first row transition metal atoms.

Recent chemical studies have focused on the structure, energetics, and reactivity of molecules and have included:

  • Structure and bond energies of chemically-bound molecules, e.g., AH, A2 , and AB, where A and B are first (B-F) and second (Al-Cl) row atoms; HCO; CHn and C2Hn; HSO, SO and SO2.
  • Structure and binding energies of hydrogen-bonded clusters, e.g., (HF)2 , (H2O)n, and MX(H2O)n, where M is an alkali atom (Li, Na) and X is a halogen atom (F, Cl).
  • Structure and binding energies of weakly bound molecular complexes, e.g., Rg2 and Rg–HX where Rg is a rare gas atom (He, Ne, Ar) and X is a halogen atom (F, Cl) and N2–HF.
  • Energetics of reactions important in fundamental chemistry, e.g., F + H2 and Cl + HCl and in environmental chemistry, e.g., OH- + CHnCl(4-n).
  • Electron affinities of molecules, e.g., CH, OH, C2 , O2 , CN, HCO, and NO, and proton affinities of molecules, e.g., H2O and NH3.
  • Potential energy curves for the low-lying electronic states of transition metal species, e.g., VC, CrC and TiCH.

These state-of-the-art calculations allow insights into the nature of molecular structure and energetics that is difficult to obtain from experimental studies alone. In addition, they allow the properties of molecules to be predicted to an unprecedented level of accuracy, competing with all but the most sophisticated experimental studies.

Educational Interests
There have been a number of advances in theoretical and computational chemistry in the last decade that allow us to place computational molecular modeling on a firm rational footing. Unfortunately, little of this work is found in textbooks. A senior/first year graduate level course is being developed to provide students with an understanding of the fundamentals of electronic structure theory and the use of computational models to predict the structure, energetics, and reactivity of molecules. Topics covered include molecular orbital and generalized valence bond theories of molecular electronic structure; treatment of electron correlation (configuration interaction, perturbation theory, and coupled cluster approaches); calculation of the spectroscopic properties of molecules; reaction paths and valleys for understanding the molecular details of chemical reactivity; and transition state and variational transition state theories for calculating the rates of chemical reactions.

Publications

"Ab initio study of the electronic structure of manganese carbide," Apostolos Kalemos, Thom H. Dunning, Jr., and Aristides Mavridis, Journal of Chemical Physics 124, 154308 (2006).

"Electron Affinity of NO," C. A. Arrington, T. H. Dunning, Jr., and D. E. Woon, Journal of Physical Chemistry A 111, 11185-11188 (2007)

"Transforming Chemistry Education through Computational Science," Shawn C. Sendlinger, Don J. DeCoste, Thom H. Dunning, Diana Avalos Dummitt, Eric Jakobsson, Dave R. Mattson, and Edee Norman Wiziecki, Computing in Science & Engineering 4, 34-39 (2008).

"The electronic structure of the two lowest states of CuC," Apostolos Kalemos, Thom H. Dunning, Jr., and Aristides Mavridis, Journal of Chemical Physics 129, 174306 (2008).

"A comparison between polar covalent bonding and hypervalent recoupled pair bonding in diatomic chalcogen halide species {O,S,Se}x{F,Cl,Br}," David E. Woon and Thom H. Dunning, Jr., Molecular Physics (in press).

Awards

  • Woodrow Wilson Fellowship (1965-6)
  • National Science Foundation Fellowship (1966-9)
  • Fellow, American Physical Society (1992)
  • Fellow, American Association for the Advancement of Science (1992)
  • E. O. Lawrence Award in Chemistry (1997)
  • Distinguished Associate Award, Office of Science, U.S. Department of Energy (2001)

Highlights

Patents

Photo of Thom H. Dunning, Jr.