H. Bernhard Schlegel Title Professor Division Physical Education B.Sc., University of Waterloo, Canada, 1972 Ph.D., Queen’s University, Canada, 1975 Postdoctoral Fellow, 1976, Princeton University and 1977, Carnegie-Mellon University Industrial, 1978-80, Merck, Sharp and Dohme Office Chem 371 Phone (313)577-2562 E-Mail Group http://chem.wayne.edu/schlegel

With theoretical calculations it is possible to investigate details of chemical reactions and molecular properties that are often difficult to study experimentally. Molecular orbital computations can be used to explore potential energy surfaces for reactions, determine equilibrium geometries, locate transition states, follow reaction paths and choose between different proposed reaction mechanisms. Heats of formation, NMR spectra, vibrational spectra and a variety of molecular properties can also be calculated reliably by ab initio molecular orbital methods. These calculations are particularly useful for highly reactive molecules and unstable intermediates that are problematic to observe experimentally.

Our lab is involved in both the development and the application of new methods in ab initio molecular orbital (MO) theory. The development efforts are centered around analytical energy derivatives and the use of these derivatives to explore potential energy surfaces. Over the past 20 years, our group and others have developed efficient computer programs to calculate energy derivatives for a variety of levels of ab initio MO theory. Our current efforts include the development of new algorithms using derivatives for geometry optimization, searching for transition states and following reaction paths. Recently we have devised an efficient code to compute classical trajectories for molecular dynamics directly from the MO calculations. To aid in the study of radicals, we have developed spin projection methods to obtain more accurate energetics for open shell systems.

The remarkable advances in quantum chemical software and the rapid increase in the speed of computers have opened new realms of chemistry for investigation by ab initio molecular orbital methods. Many of our applications of quantum chemical calculations are in direct collaboration with experimental groups in order to maximize the benefits of our studies. In the area of organic chemistry, we have examined reactions involving peroxides, peroxy acids and dioxiranes, reactivity and rearrangements of organic radicals, and the behavior of nitric oxide releasing agents. Within physical chemistry, we are looking at surface reactions using embedded cluster methods, and are studying reaction path branching by ab initio trajectory methods. In applications to biochemistry, we are using electronic structure methods to examine the modulation of chemical reactivity by interactions in the active sites of enzymes. In the area of materials, we have a long standing interest in chemical vapor deposition (CVD). We have studied the thermochemistry and reactivity of a variety of systems pertaining to silicon, zinc oxide and titanium-nitride CVD. Our new efforts in the materials area are directed toward thin film organic semiconductors.

Li, J.; Shaik, S.; Schlegel, H. B.; A Single Transition State Serves Two Mechanisms. The Branching Ratio for CH₂O•¯ + H₃Cl on Improved Potential Energy Surfaces. J. Phys. Chem. A 2006, 110, 2801-2806.

Li, J.; Cross, J. B.; Vreven, T.; Meroueh, S. O.; Mobashery, S.; Schlegel, H. B.; A Theoretical Study of Lysine Carboxylation in Proteins: OXA- 10 b Lactamase. Proteins 2005, 61, 246-257.

Smith, S. M.; Li, X.; Alexei N. Markevitch, A. N.; Romanov, D. A.; Robert J. Levis, R. J.; Schlegel, H. B.; Numerical Simulation of Nonadiabatic Electron Excitation in the Strong Field Regime: 2. Linear Polyene Cations. J. Phys. Chem. A 2005, 109, 10527-10534.

Halls, M. D.; Schlegel, H. B. “Chemistry Inside Carbon Nanotubes: Enhancement of the Menshutkin SN2 Reaction”, J. Phys. Chem. B 2002, 106, 1921–1925.

Li, X.; Liu, L.; Schlegel, H. B. “On the Physical Origin of Blue-Shifted Hydrogen Bonds”, J. Am. Chem. Soc. 2002, 124, 9639–9647.