A multiscale approach to coupled nuclear and electronic dynamics. II. Exact and approximated evaluation of nonradiative transition rates.

This work follows a companion article, which will be referred to as Paper I [Campeggio et al., J. Chem.

A multiscale approach to coupled nuclear and electronic dynamics. I. Quantum-stochastic Liouville equation in natural internal coordinates.

Multiscale methods are powerful tools to describe large and complex systems. They are based on a hierarchical partitioning of the degrees of freedom (d.o.

Ethanol electro-oxidation reaction on the Pd(111) surface in alkaline media: insights from quantum and molecular mechanics.

The ethanol electro-oxidation catalyzed by Pd in an alkaline environment involves several intermediate reaction steps promoted by the hydroxyl radical, OH. In this work, we report on the dynamical paths of the first step of this oxidation reaction, namely the hydrogen atom abstraction CHCHOH + OH → CHCHOH + HO, occurring at the Pd(111) surface and address the thermodynamic stability of the adsorbed reactants by means of quantum and molecular mechanics calculations, with special focus on the effect of the solvent. We have found that the impact of the solvent is significant for both ethanol and OH, contributing to a decrease in their adsorption free energies by a few dozen kcal mol with respect to the adsorption energy under vacuum.

Parameter free evaluation of S2 reaction rates for halide substitution in halomethane.

We estimate the kinetic constants of a series of archetypal S2 reactions, , the nucleophilic substitutions of halides in halomethane. A parameter free, multiscale approach recently developed [Campeggio , , 2020, , 3455] is employed. The protocol relies on quantum mechanical calculations for the description of the energy profile along the intrinsic reaction coordinate, which is then mapped onto a reaction coordinate conveniently built for the reactive process.

Multiscale modeling of reaction rates: application to archetypal S2 nucleophilic substitutions.

We propose an approach to the evaluation of kinetic rates of elementary chemical reactions within Kramers' theory based on the definition of the reaction coordinate as a linear combination of natural, pseudo Z-matrix, internal coordinates of the system. The element of novelty is the possibility to evaluate the friction along the reaction coordinate, within a hydrodynamic framework developed recently [J. Campeggio et al.