Hans Martin Senn, Artur Michalak, Tom Ziegler

Department of Chemistry, University of Calgary,
Calgary, Alberta T2N 1N4, Canada

A technique capable of performing ab initio molecular-dynamics (AIMD) simulations along the intrinsic reaction path has recently been introduced [1]. It allows to obtain free-energy differences using slow-growth thermodynamic integration with only minimal hysteresis due to the optimal choice of the reac-tion coordinate.
We have applied this technique to a series of classical, prototypical organic reactions, such as the Diels­Alder reaction of 1,3-butadiene and ethene form-ing cyclohexene, and the Wittig reaction of acetaldehyde and methyle-netrimethylphosphorane yielding propene and trimethylphosphane oxide. We will discuss the pertinent differences between the static picture, as obtained from conventional IRC calculations, and a dynamical description of the reac-tion, as elucidated by slow-growth AIMD simulations along the IRP.

[1]  A. Michalak and T. Ziegler, J. Phys. Chem. A (2001) 105 4333.