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| Many catalytic processes involve hydrogen transfers such as enzymatically facilitated reactions in our bodies or the steam-reforming of methane during the Haber-Bosch process enhanced by metals. These hydrogen transfers are impacted by quantum effects such as atom tunnelling through the energy barriers of the reaction instead of going over it.
Hydrogen tunnelling increases the reaction rates compared to the classical transition state theory model especially at low temperature.
The imaginary free energy instanton method allows to investigate the role of tunnelling in high dimensional systems with several thousand degrees of freedom. The method is based on Feynman's path integral formalism to describe quantities from statistical quantum mechanics. The instanton is the most-likely tunnelling path obtained by optimising a ring polymer instead of running full quantum dynamics.
In this talk the instanton method will (a) be explained by linking it to differential geometry, oscillatory integrals, and dynamical systems theory and (b) be applied to a couple of large chemical systems.
The aim is to give a combined chemical and mathematical perspective on recent advances in quantum rate theory and the challenges to obtain efficient and reliable simulation methods. |
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