In this presentation, application of quantum chemistry methods to the problems of multidimensional tunneling will be demonstrated. The rate limiting-step of many chemically and biologically important processes is proton, hydrogen or hydride transfer reactions. Due to the light mass of the transferring hydrogen atom, nuclear quantum effects, such as tunneling and zero-point energy, may play a significant role. Quantum tunneling is occasionally experimentally observed in reactions of enzyme catalysis [1]. A reaction rate theory based on the stationary phase approximation to the Feynman path integral has been recently proposed [2], which is capable to correctly describe nuclear quantum effects in multiatomic systems at arbitrary temperatures. The attractive feature of this approach is its weak scaling with system size. The latter allows one to calculate electronic potential energy surface on the fly using quantum chemistry methods, and makes the proposed approach an attractive practical method that is capable to treat both nuclei and electrons at the quantum mechanical level. The approach is illustrated with several examples.  [1] Quantum Tunnelling in Enzyme-Catalysed Reactions, edited by R. K. Allemann, N. S. Scrutton, RSC Publishing, Cambridge, UK, (2009);[2] M. Kryvohuz, J. Chem. Phys. 134 , 114103 (2011);

Multidimensional tunneling with on-the-fly calculation of reactive potential energy surface

245th National Meeting (2013)

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