Cavity-catalyzed hydrogen transfer dynamics in an entangled molecular ensemble under vibrational strong coupling. Issue 16 (17th April 2023)

• Record Type: Journal Article
• Authors: Fischer, Eric W.; Saalfrank, Peter
• Is Part Of: Physical chemistry chemical physics. Volume 25:Issue 16(2023)
• Page Start: 11771
• Page End: 11779
• Publication Date: 2023-04-17
• Subjects: Chemistry, Physical and theoretical -- Periodicals; 541.3
• DOI: 10.1039/d3cp00175j
• Languages: English
• ISSNs: 1463-9076

Abstract

Abstract : Light-matter entanglement in a cavity-catalysed hydrogen transfer ensemble reaction model is studied, its relevance for thermal rate enhancement is discussed and entanglement-related deviations from reactive single-molecule models are analyzed. Abstract : Microcavities have been shown to influence the reactivity of molecular ensembles by strong coupling of molecular vibrations to quantized cavity modes. In quantum mechanical treatments of such scenarios, frequently idealized models with single molecules and scaled, effective molecule-cavity interactions or alternatively ensemble models with simplified model Hamiltonians are used. In this work, we go beyond these models by applying an ensemble variant of the Pauli–Fierz Hamiltonian for vibro-polaritonic chemistry and numerically solve the underlying time-dependent Schrödinger equation to study the cavity-induced quantum dynamics in an ensemble of thioacetylacetone (TAA) molecules undergoing hydrogen transfer under vibrational strong coupling (VSC) conditions. Beginning with a single molecule coupled to a single cavity mode, we show that the cavity indeed enforces hydrogen transfer from an enol to an enethiol configuration with transfer rates significantly increasing with light-matter interaction strength. This positive effect of the cavity on reaction rates is different from several other systems studied so far, where a retarding effect of the cavity on rates was found. It is argued that the cavity "catalyzes" the reaction by transfer of virtual photons to the molecule. The same concept applies to ensembles with up to N = 20 TAA molecules coupled to a single cavity mode, where an additional, significant, ensemble-induced collective isomerization rate enhancement is found. The latter is traced back to complex entanglement dynamics of the ensemble, which we quantify by means of von Neumann-entropies. A non-trivial dependence of the dynamics on ensemble size is found, clearly beyond scaled single-molecule models, which we interpret as transition from a multi-mode Rabi to a system-bath-type regime as N increases.