Gudem Mahesh, Kowalewski Markus
Department of Physics, Stockholm University, Albanova University Centre, SE-106 91 Stockholm, Sweden.
J Phys Chem A. 2023 Nov 16;127(45):9483-9494. doi: 10.1021/acs.jpca.3c05664. Epub 2023 Oct 16.
Chemiluminescence is a thermally activated chemical process that emits a photon of light by forming a fraction of products in the electronic excited state. A well-known example of this spectacular phenomenon is the emission of light in the firefly beetle, where the formation of a four-membered cyclic peroxide compound and subsequent dissociation produce a light-emitting product. The smallest cyclic peroxide, dioxetane, also exhibits chemiluminescence but with a low quantum yield as compared to that of firefly dioxetane. Employing the strong light-matter coupling has recently been found to be an alternative strategy to modify the chemical reactivity. In the presence of an optical cavity, the molecular degrees of freedom greatly mix with the cavity mode to form hybrid cavity-matter states called polaritons. These newly generated hybrid light-matter states manipulate the potential energy surfaces and significantly change the reaction dynamics. Here, we theoretically investigate the effects of a strong light-matter interaction on the chemiluminescent reaction of dioxetane using the extended Jaynes-Cummings model. The cavity couplings corresponding to the electronic and vibrational degrees of freedom have been included in the interaction Hamiltonian. We explore how the cavity alters the ground- and excited-state path energy barriers and reaction rates. Our results demonstrate that the formation of excited-state products in the dioxetane decomposition process can be either accelerated or suppressed, depending on the molecular orientation with respect to the cavity polarization.
化学发光是一种热激活化学过程，通过形成处于电子激发态的部分产物来发射光子。这种壮观现象的一个著名例子是萤火虫甲虫发光，其中四元环过氧化物化合物的形成及随后的解离产生发光产物。最小的环过氧化物二氧杂环丁烷也表现出化学发光，但与萤火虫二氧杂环丁烷相比量子产率较低。最近发现利用强光与物质的强耦合是一种改变化学反应活性的替代策略。在光学腔存在的情况下，分子自由度与腔模极大地混合形成称为极化激元的混合腔 - 物质态。这些新产生的混合光 - 物质态操纵势能面并显著改变反应动力学。在此，我们使用扩展的杰恩斯 - 卡明斯模型从理论上研究强光与物质相互作用对二氧杂环丁烷化学发光反应的影响。相互作用哈密顿量中包含了与电子和振动自由度对应的腔耦合。我们探索腔如何改变基态和激发态路径的能量势垒以及反应速率。我们的结果表明，在二氧杂环丁烷分解过程中激发态产物的形成可以根据分子相对于腔极化的取向而加速或受到抑制。
