Simulation of Vibronic Strong Coupling and Cavity-Modified Hydrogen Tunneling Dynamics

TL;DR

This paper introduces a semiclassical quantum dynamics method to simulate vibronic strong coupling and cavity effects on hydrogen tunneling, enabling the study of polariton-influenced chemical reactions beyond traditional approximations.

Contribution

The paper develops a novel semiclassical NEO-TDCI approach that treats electrons and nuclei quantum mechanically while modeling the cavity classically, allowing comprehensive simulation of vibronic and electronic strong coupling regimes.

Findings

Cavity coupling can modify hydrogen tunneling dynamics.

The method captures both electronic and vibrational strong coupling effects.

Simulations show cavity modes influence nuclear motions even at typical ESC frequencies.

Abstract

Polaritons have gained significant attention for the tantalizing possibility of modifying chemical properties and dynamics by coupling molecules to resonant cavity modes to create hybrid light-matter quantum states. Herein, we implement the semiclassical nuclear-electronic orbital time-dependent configuration interaction (NEO-TDCI) approach, which treats electrons and specified nuclei on the same quantum mechanical level, while treating the cavity mode classically. This ab initio dynamics approach can describe both the electronic strong coupling (ESC) and the vibrational strong coupling (VSC) regimes at the same level of theory without invoking the Born-Oppenheimer separation between the quantum nuclei and the electrons. This approach is used to simulate resonant and off-resonant vibronic strong coupling, where the cavity mode couples to one or many vibronic transitions associated with joint electronic-nuclear excitations within a vibronic progression. In this case, the cavity mode couples to nuclear motions even for cavity frequencies typically associated with ESC. This approach is also used to illustrate that coupling a molecule to a cavity mode can alter hydrogen tunneling dynamics. The semiclassical NEO-TDCI approach provides the foundation for investigating how polaritons may be able to influence chemical reactions involving tunneling and nonadiabatic effects.