Ab initio study on the dynamics and spectroscopy of collective rovibrational polaritons

TL;DR

This study uses ab initio models to explore how molecules interact with resonant IR radiation inside a cavity, revealing detailed collective effects on energy levels, spectra, and molecular dynamics.

Contribution

It introduces an efficient theoretical approach employing rotationally resolved models to analyze cavity-mediated molecular interactions and their effects on rovibrational spectra.

Findings

Identification of cavity-mediated energy level shifts

Observation of intensity borrowing in absorption spectra

Detection of intermolecular energy transfer during dynamics

Abstract

Accurate rovibrational molecular models are employed to gain insight in high-resolution into the collective effects and intermolecular processes arising when molecules in the gas phase are interacting with a resonant infrared (IR) radiation mode. An efficient theoretical approach is detailed and numerical results are presented for the HCl, H$_2$O and CH$_4$ molecules confined in an IR cavity. It is shown that by employing a rotationally resolved model for the molecules, revealing the various cavity-mediated interactions between the field-free molecular eigenstates, it is possible to obtain a detailed understanding of the physical processes governing the energy level structure, absorbtion spectra, and dynamic behavior of the confined systems. Collective effects, arising due to the cavity-mediated interaction between molecules, are identified in energy level shifts, in intensity borrowing effects in the absorbtion spectra, and in the intermolecular energy transfer occurring during Hermitian or non-Hermitian time propagation.