Kramers problem for nonequilibrium current-induced chemical reactions

TL;DR

This paper develops a theoretical framework using nonequilibrium Green's functions and Langevin dynamics to control chemical reactions via tunneling electron current, showing how bias voltage influences reaction barriers and catalysis.

Contribution

It introduces a novel approach combining Keldysh Green's functions with Langevin equations to model current-induced chemical reactions under nonequilibrium conditions.

Findings

Reaction barriers can be tuned by bias voltage.

Asymmetric electrode coupling enables current-controlled catalysis.

Reaction can be halted or accelerated depending on current polarity.

Abstract

We discuss the use of tunneling electron current to control and catalyze chemical reactions. Assuming the separation of time scales for electronic and nuclear dynamics we employ the Langevin equation for the reaction coordinate. The Langevin equation contains current-induced forces and is used to define nonequilibrium, effective potential energy surface for current-carrying molecular systems. The current-induced forces are computed via Keldysh nonequilibrium Green's functions. Once the nonequilibrium, current-depended potential energy surface is defined, the chemical reaction is modeled as an escape of a Brownian particle from the potential well. We demonstrate that the barrier between the reactant and the product states can be controlled by the bias voltage. When the molecule is asymmetrically coupled to the electrodes, the reaction can be catalyzed or stopped depending on the polarity of the tunneling current.