Related papers: Comparison of classical reaction paths and tunneli…
Quantum tunneling reactions play a significant role in chemistry when classical pathways are energetically forbidden, be it in gas phase reactions, surface diffusion, or liquid phase chemistry. In general, such tunneling reactions are…
We calculated reaction rate constants including atom tunneling of the reaction of dihydrogen with the hydroxy radical down to a temperature of 50 K. Instanton theory and canonical variational theory with microcanonical optimized…
The four-electron oxygen reduction reaction on Pt catalyst in alkaline solution undergoes proton transfer via tunneling mechanism. The hydrogen/deuterium kinetic isotopic rate constant ratio (kH/kD ) = 32 in a low overpotential region,…
The tunneling reaction H$_2$ + D$^-$ $\rightarrow$ HD + H$^-$ was studied in a recent experimental work at low temperatures (10, 19, and 23~K) by Endres {\it et al.}, Phys. Rev. A {\bf 95}, 022706 (2017). An upper limit of the rate…
Recent studies of neutral gas-phase reactions characterized by barriers show that certain complex forming processes involving light atoms are enhanced by quantum mechanical tunneling at low temperature. Here, we performed kinetic…
We present a combined experimental and theoretical study focussing on the quantum tunneling of atoms in the reaction between CH4 and OH. The importance of this reaction pathway is derived by investigating isotope substituted analogs.…
Quantum mechanical tunneling of atoms is increasingly found to play an important role in many chemical transformations. Experimentally, atom-tunneling can be indirectly detected by temperature-independent rate constants at low temperature…
We consider the role of quantum effects in the transfer of hyrogen-like species in enzyme-catalysed reactions. This study is stimulated by claims that the observed magnitude and temperature dependence of kinetic isotope effects imply that…
OH radicals play a key role as an intermediate in the water formation chemistry of the interstellar medium. For example the reaction of OH radicals with H$_2$ molecules is among the final steps in the astrochemical reaction network starting…
Semiclassical instanton theory is a form of quantum transition-state theory which can be applied to computing thermal reaction rates for complex molecular systems including quantum tunneling effects. There have been a number of attempts to…
Instanton theory relates the rate constant for tunneling through a barrier to the periodic classical trajectory on the upturned potential energy surface whose period is $\tau=\hbar/(k_{\rm B}T)$. Unfortunately, the standard theory is only…
We explore the relation between the quantum and semiclassical instanton approximations for the reaction rate constant. From the quantum instanton expression, we analyze the contributions to the rate constant in terms of minimum-action paths…
Quantum proton tunneling (QPT) in the two representative multi-electron/-proton transfer electrode processes, i.e. hydrogen evolution reaction (HER) and oxygen reduction reaction (ORR), was investigated by using polycrystalline platinum…
We calculated reaction rate constants including atom tunneling for the hydrogen abstraction reaction CH3OH+H -> CH2OH+H2 with the instanton method. The potential energy was fitted by a neural network, that was trained to…
The quantum motions of hydrogen (H) atoms play an important role in the dynamical properties and functionalities of condensed phase materials as well as biological systems. In this work, based on the transfer matrix method and…
We report on a study of the exchange tunneling reaction D+HD$\rightarrow$D$_{2}$+H in a pure solid HD matrix and in a D$_{2}$ matrix with 0.23$\%$ HD admixture at temperatures between 130$\,$mK and 1.5$\,$K. We found that the exchange…
Canonical instanton theory is known to overestimate the rate constant close to a system-dependent crossover temperature and is inapplicable above that temperature. We compare the accuracy of the reaction rate constants calculated using…
Hawking radiation as tunneling by Hamilton-Jacobi method beyond semiclassical approximation is analysed. We compute all quantum corrections in the single particle action revealing that these are proportional to the usual semiclassical…
Instanton theory is an established method to calculate rate constants of chemical reactions including atom tunneling. Technical and methodological improvements increased its applicability. Still, a large number of energy and gradient…
The final step of the water formation network on interstellar grain surfaces starting from the H + O$_2$ route is the reaction between H and H$_2$O$_2$. This reaction is known to have a high activation energy and therefore at low…