Cavity Catalysis ‒Accelerating Reactions under Vibrational Strong Coupling‒

Abstract

<p>In conventional catalysis the reactants interact with specific sites of the catalyst in such a way that the reaction barrier is lowered and the reaction rate is accelerated. Here we take a radically different approach to catalysis by strongly coupling the vibrations of the reactants to the vacuum electromagnetic field of a cavity. To demonstrate the possibility of such cavity catalysis, we have studied hydrolysis reactions under strong coupling of the OH stretching mode of water to a Fabry-Pérot (FP) microfluidic cavity mode. This results in an exceptionally large Rabi splitting energy ℏΩ<sub>R</sub> of 92 meV (740 cm<sup>−1</sup>), indicating the system is in vibrational ultra-strong coupling (V-USC) regime and we have found that it enhances the hydrolysis reaction rate of cyanate ions by 10<sup>2</sup> times and that of ammonia borane by 10<sup>4</sup> times. This catalytic ability is shown to depend only upon the cavity tuning and the coupling ratio. Given the vital importance of water for life and human activities, we expect our finding not only offers an unconventional way of controlling chemical reactions by ultra-strong light-matter interactions, but also changes the landscape of chemistry in a fundamental way.</p>

Multi-level quantum Rabi model for anharmonic vibrational polaritons

“…9a. This occurs because states |Ψ 22 and |Ψ 23 do have uncoupled components that interact via the photonic selection rule ∆n ± 1, but their weight in the eigenfunction is comparatively small.…”

“…Several recent studies on vibrational strong coupling (VSC) within the ground electronic state have shown that chemical reactions can proceed through novel pathways in comparison with free space. Under VSC, reactions may be inhibited or catalyzed, or the product * Electronic address: felipe.herrera.u@usach.cl branching ratios tilted [7,16,22,23]. For instance, by strongly coupling the carbon-silyl (Si-C) bond stretching vibration of 1-phenyl-2-trimethylsilylacetylene to the electromagnetic vacuum of a resonant infrared microfluidic cavity, the rate of Si-C bond breakage has been shown to decrease by a moderate factor of order unity [16].…”

“…For instance, by strongly coupling the carbon-silyl (Si-C) bond stretching vibration of 1-phenyl-2-trimethylsilylacetylene to the electromagnetic vacuum of a resonant infrared microfluidic cavity, the rate of Si-C bond breakage has been shown to decrease by a moderate factor of order unity [16]. In another recent study [22], the catalytic effect of VSC on the hydrolysis of cyanate ions and ammonia borane, under coupling of a Fabry-Pérot cavity witht the broad OH infrared absorption band of water was demonstrated. The measured increase on the reaction rate constant by two orders of magnitude relative to free space for cyanate and by four orders of magnitude for ammonia borane, is one of the first reports of cavity-enhanced reactivity, a possibility earlier predicted for electron transfer reactions in microcavities [32].…”

“…These hybrid light-matter states exhibit fundamentally novel properties in comparison with free-space vibrations. For instance, vibrational polaritons may enable the selective control of chemical reactions [21][22][23], a long-standing goal in physical chemistry [24]. Strong light-matter coupling provides a reversible way of modifying reactive processes without changing the chemical composition of materials, and also modify the radiative and non-radiative dynamics of molecular vibrations [25][26][27][28][29][30][31].…”

Benchmarking semiclassical and perturbative methods for real-time simulations of cavity-bound emission and interference

“…To describe chemical processes that are strongly correlated with quantum light [17][18][19] , requires an accurate and flexible, furthermore computationally efficient, treatment of the lightmatter interactions. Thus, in order to meet the demand of developing an ab initio theoretical description of cavity modified chemical systems, extensions to the traditional theoretical tool-kits for quantum optics and quantum chemistry are required.…”