A Nonequilibrium Molecular Dynamics Study of Infrared Perturbed Electron Transfer
journal contributionposted on 2018-07-13, 00:00 authored by Zheng Ma, Panayiotis Antoniou, Peng Zhang, Spiros S. Skourtis, David N. Beratan
Infrared (IR) excitation is known to change electron-transfer kinetics in molecules. We use nonequilibrium molecular dynamics (NEqMD) simulations to explore the molecular underpinnings of how vibrational excitation may influence nonadiabatic electron-transfer. NEqMD combines classical molecular dynamics simulations with nonequilibrium semiclassical initial conditions to simulate the dynamics of vibrationally excited molecules. We combine NEqMD with electronic structure computations to probe IR effects on electron transfer rates in two molecular species, dimethylaniline-guanosine-cytidine-anthracene (DMA-GC-Anth) and 4-(pyrrolidin-1-yl)phenyl-2,6,7-triazabicyclo[2.2.2]octatriene-10-cyanoanthracen-9-yl (PP-BCN-CA). In DMA-GC-Anth, the simulations find that IR excitation of the NH2 scissoring motion and the subsequent intramolecular vibrational energy redistribution (IVR) do not significantly alter the mean-squared donor–acceptor (DA) coupling interaction. This finding is consistent with earlier computational analysis of static systems. In PP-BCN-CA, IR excitation of the bridging CN bond changes the bridge-mediated coupling for charge separation and recombination by ∼30–40%. The methods described here enable detailed explorations of how IR excitation may perturb charge-transfer processes at the molecular scale.
dynamicnonequilibriumDMA-GC-AnthNonequilibrium Molecular Dynamics StudyPP-BCN-CAIR excitationsimulationIVRNHNEqMDchange electron-transfer kineticsprobe IR effectsDAperturb charge-transfer processesmoleculeintramolecular vibrational energy redistributionInfrared Perturbed Electron Transferelectron transfer rates