Investigating Photoinduced Proton Coupled Electron Transfer Reaction using Quasi Diabatic Dynamics Propagation

TL;DR

This paper introduces a quasi-diabatic quantum dynamics scheme to accurately simulate photoinduced proton-coupled electron transfer reactions, highlighting the importance of quantum treatment of protons and solvent effects.

Contribution

It develops a novel quasi-diabatic propagation method combining diabatic quantum dynamics with adiabatic electronic structure calculations for PI-PCET reactions.

Findings

Quantum mechanical treatment of protons is crucial for accurate dynamics.

Solvent fluctuations significantly influence proton tunneling.

The method enables on-the-fly simulation of complex PI-PCET processes.

Abstract

We investigate photoinduced proton-coupled electron transfer (PI-PCET) reaction through a recently devel- oped quasi-diabatic (QD) quantum dynamics propagation scheme. This scheme enables interfacing accurate diabatic-based quantum dynamics approaches with adiabatic electronic structure calculations for on-the-fly simulations. Here, we use the QD scheme to directly propagate PI-PCET quantum dynamics with the di- abatic Partial Linearized Density Matrix (PLDM) path-integral approach with the instantaneous adiabatic electron-proton vibronic states. Our numerical results demonstrate the importance of treating proton quan- tum mechanically in order to obtain accurate PI-PCET dynamics, as well as the role of solvent fluctuation and vibrational relaxation on proton tunneling in various reaction regimes that exhibit different kinetic iso- tope effects. This work opens the possibility to study the challenging PI-PCET reactions through accurate diabatic quantum dynamics approaches combined with efficient adiabatic electronic structure calculations.