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ResearchVan Swinderen Institute

MSC Colloquium Dieter Cremer


05 October 2006 FWN-Building 5111.0080, Nijenborgh 4, 9747 AG, Groningen
Professor Dieter Cremer
Professor Dieter Cremer
Speaker: Dieter Cremer
Affiliation: Department of Chemistry and Department of Physics, University of the Pacific, Stockton, CA 95211, USA
Title: Mechanistic and dynamic studies of organic reactions utilizing the reaction path Hamiltonian and the unified reaction valley approach
Date: Thu Oct 5, 2006
Start: 16.00 (Doors open and coffee available at 15.30)
Location: FWN-Building 5111.0080


The traditional approach to the study of reaction mechanism focuses on the calculation and description of stationary points (minima and first order saddle points) along the reaction path. With the help of intrinsic reaction coordinate (IRC) calculations one can straightforwardly test whether the stationary points are really connected by minimum energy paths on the potential energy surface (PES). A more elaborate approach to verifying the net of minimum energy paths connecting TSs and intermediates characteristic of a given reaction mechanism is based on reaction path studies which employ the reaction path Hamiltonian1 and the unified reaction valley approach (URVA)2. It is demonstrated how the application of URVA leads to a detailed description of chemical reactions from the point of the first van der Waals interactions between the reactants through the preparation region (in which the reaction partners are prepared for the chemical reaction) up to the transition state region (in which the actual chemical processes such as bond breaking and bond forming take place). Particular consideration is given to changes in the reaction path direction and the reaction path curvature since the latter provide information on energy transfer and energy dissipation, selective rate enhancement by mode pumping, and the sequence of electronic structure changes. It is shown how symmetry allowed and symmetry forbidden reactions differ with regard to their reaction mechanism. The possible existence of hidden intermediates is discussed and their role in the reaction mechanism is clarified.

1) Miller, W.H.; Handy, N.C.;  Adams, J.E.  J. Chem. Phys. 1980, 72, 99.
2) Konkoli, Z.; Kraka, E.; Cremer, D. J. Phys. Chem. A, 1997, 101, 1742.

Last modified:12 September 2014 11.22 a.m.