Semiclassical Real-Time Nuclear-Electronic Orbital Dynamics for Molecular Polaritons: Unified Theory of Electronic and Vibrational Strong Couplings

TL;DR

This paper introduces a semiclassical real-time nuclear-electronic orbital approach to model molecular polaritons, capturing electronic and vibrational strong couplings and nuclear quantum effects, with implications for controlling chemical reactions via optical cavities.

Contribution

It develops a unified semiclassical method combining classical cavity modes with quantum nuclear-electronic dynamics, including nuclear quantum effects, for the first time.

Findings

Cavity suppresses excited state proton transfer influenced by polaritonic potential.

The approach captures the impact of cavity on nuclear-electronic dynamics.

Provides a basis for studying collective strong coupling in quantum systems.

Abstract

Molecular polaritons have become an emerging platform for remotely controlling molecular properties through strong light-matter interactions. Herein, a semiclassical approach is developed for describing molecular polaritons by self-consistently propagating the real-time dynamics of classical cavity modes and a quantum molecular subsystem described by the nuclear-electronic orbital (NEO) method, where electrons and specified nuclei are treated quantum mechanically on the same level. This semiclassical real-time NEO approach provides a unified description of electronic and vibrational strong couplings and describes the impact of the cavity on coupled nuclear-electronic dynamics while including nuclear quantum effects. For a single o-hydroxybenzaldehyde molecule under electronic strong coupling, this approach shows that the cavity suppression of excited state intramolecular proton transfer is influenced not only by the polaritonic potential energy surface but also by the timescale of the chemical reaction. This work provides the foundation for exploring collective strong coupling in nuclear-electronic quantum dynamical systems within optical cavities.