A1 Journal article (refereed)
Multi-scale dynamics simulations of molecular polaritons : the effect of multiple cavity modes on polariton relaxation (2021)

Tichauer, R. H., Feist, J., & Groenhof, G. (2021). Multi-scale dynamics simulations of molecular polaritons : the effect of multiple cavity modes on polariton relaxation. Journal of Chemical Physics, 154(10), Article 104112. https://doi.org/10.1063/5.0037868

JYU authors or editors

Tichauer, Ruth
Groenhof, Gerrit

Publication details

All authors or editors: Tichauer, Ruth H.; Feist, Johannes; Groenhof, Gerrit

Journal or series: Journal of Chemical Physics

ISSN: 0021-9606

eISSN: 1089-7690

Publication year: 2021

Volume: 154

Issue number: 10

Article number: 104112

Publisher: AIP Publishing

Publication country: United States

Publication language: English

DOI: https://doi.org/10.1063/5.0037868

Publication open access: Not open

Publication channel open access:

Publication is parallel published (JYX): https://jyx.jyu.fi/handle/123456789/74702

Abstract

Coupling molecules to the confined light modes of an optical cavity is showing great promise for manipulating chemical reactions. However, to fully exploit this principle and use cavities as a new tool for controlling chemistry, a complete understanding of the effects of strong light–matter coupling on molecular dynamics and reactivity is required. While quantum chemistry can provide atomistic insight into the reactivity of uncoupled molecules, the possibilities to also explore strongly coupled systems are still rather limited due to the challenges associated with an accurate description of the cavity in such calculations. Despite recent progress in introducing strong coupling effects into quantum chemistry calculations, applications are mostly restricted to single or simplified molecules in ideal lossless cavities that support a single light mode only. However, even if commonly used planar mirror micro-cavities are characterized by a fundamental mode with a frequency determined by the distance between the mirrors, the cavity energy also depends on the wave vector of the incident light rays. To account for this dependency, called cavity dispersion, in atomistic simulations of molecules in optical cavities, we have extended our multi-scale molecular dynamics model for strongly coupled molecular ensembles to include multiple confined light modes. To validate the new model, we have performed simulations of up to 512 Rhodamine molecules in red-detuned Fabry–Pérot cavities. The results of our simulations suggest that after resonant excitation into the upper polariton at a fixed wave vector, or incidence angle, the coupled cavity-molecule system rapidly decays into dark states that lack dispersion. Slower relaxation from the dark state manifold into both the upper and lower bright polaritons causes observable photo-luminescence from the molecule–cavity system along the two polariton dispersion branches that ultimately evolves toward the bottom of the lower polariton branch, in line with experimental observations. We anticipate that the more realistic cavity description in our approach will help to better understand and predict how cavities can modify molecular properties.

Keywords: quantum chemistry; molecular dynamics; polaritons; photoluminescence

Free keywords: quantum chemistry; quantum mechanical/molecular mechanical calculations; molecular dynamics; molecular properties; photoluminescence; dark states; atomistic simulations

Fields of science: