Polariton relaxation under vibrational strong coupling: Comparing cavity molecular dynamics simulations against Fermi's golden rule rate

Abstract

Under vibrational strong coupling (VSC), the formation of molecular polaritons may significantly modify the photo-induced or thermal properties of molecules. In an effort to understand these intriguing modifications, both experimental and theoretical studies have focused on the ultrafast dynamics of vibrational polaritons. Here, following our recent work [J. Chem. Phys., 154, 094124, (2021)], we systematically study the mechanism of polariton relaxation for liquid CO2 under a weak external pumping. Classical cavity molecular dynamics (CavMD) simulations show that polariton relaxation results from the combined effects of (i) cavity loss through the photonic component and (ii) dephasing of the bright-mode component to vibrational dark modes as mediated by intermolecular interactions. The latter polaritonic dephasing rate is proportional to the product of the weight of the bright mode in the polariton wave function and the spectral overlap between the polariton and dark modes. Both these factors are sensitive to parameters such as the Rabi splitting and cavity mode detuning. Compared to a Fermi's golden rule calculation based on a tight-binding harmonic model, CavMD yields a similar parameter dependence for the upper polariton relaxation lifetime but sometimes a modest disagreement for the lower polariton. We suggest that this disagreement results from polariton-enhanced molecular nonlinear absorption due to molecular anharmonicity, which is not included in our analytical model. We also summarize recent progress on probing nonreactive VSC dynamics with CavMD.

16 pages, 6 figures

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• Cavity molecular dynamics simulations of vibrational polariton enhanced molecular nonlinear absorption
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• Exact solution of polaritonic systems with arbitrary light and matter frequency-dependent losses

Cited by in corpus (9)

• QM/MM Modeling of Vibrational Polariton Induced Energy Transfer and Chemical Dynamics
• Vibrational polariton transport in disordered media
• Dissociation dynamics of a diatomic molecule in an optical cavity
• Collective response in light-matter interactions: The interplay between strong coupling and local dynamics
• Selective Excitation of IR-Inactive Modes via Vibrational Polaritons: Insights from Atomistic Simulations
• Unraveling Abnormal Collective Effects via the Non-Monotonic Number Dependence of Electron Transfer in Confined Electromagnetic Fields
• Dissipative and dispersive cavity optomechanics with a frequency-dependent mirror
• Polariton-induced Purcell effects via a reduced semiclassical electrodynamics approach
• Coherent nonlinear optical probe for cavity-dressed vibrational mode mixing: Multidimensional double-quantum coherence and photon-echo spectroscopy