CAREER: Gas-Phase Molecular Polaritons: A New Platform for Chemistry under Strong Light-Matter Coupling

在化学系化学结构，动力学和机制-A（CSDM-A）计划的支持下，普林斯顿大学的Marissa Weichman正在研究气相化学过程如何在与光的强烈相互作用下进行。当分子被封闭在一个光学腔中时，也就是说，在一个由反射镜组成的装置中，可以形成一个强大的受限光场，称为极化激元的新状态可以形成。这些系统表现出一些不寻常的光的波动性质，也似乎表现出不同于普通分子的反应性和光化学。极化激元分子的化学原理目前还没有被很好地理解。Weichman实验室正在研究强腔耦合下孤立气相分子的低温化学，以阐明最简单的分子极化激元的行为。这些发现有可能为极化激元技术在化学、材料科学和量子信息科学中的实际应用提供信息。Weichman教授还在普林斯顿大学改革本科量子化学课程，目标是扩大量子科学研究社区和劳动力的参与。Weichman实验室将专注于原始气相测量，其中极化激元反应动力学可以用量子态特异性进行研究，而不会出现溶剂化的并发症。虽然分子极化激元现在在液体和固态系统中已经很好地建立起来，但对于气相分子来说，获得足够强的光-物质相互作用仍然是一个挑战。Weichman实验室在低温下访问气相强耦合的制度，其中分子配分函数很小，不均匀的线宽很窄。低温缓冲气室允许制备冷的、致密的分子系综。该光源与反馈稳定的Fabry-Pérot光学腔和精密激光方案相结合，以设计气相分子中单个振转跃迁的强耦合。Weichman实验室将利用这一仪器来研究基准化学过程，包括双分子反应、光解离和光异构化，在腔耦合下如何发生。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

With support from the Chemical Structure, Dynamics, and Mechanisms-A (CSDM-A) Program in the Division of Chemistry, Marissa Weichman of Princeton University is studying how gas-phase chemical processes proceed under strong interactions with light. When molecules are enclosed within an optical cavity, that is, in a device built from reflective mirrors that create a strong confined light field, new states called polaritons can form. These systems exhibit some of the unusual wave-like properties of light and also appear to demonstrate reactivity and photochemistry distinct from ordinary molecules. The principles governing the chemistry of polaritonic molecules are not currently well understood. The Weichman Lab is studying the low-temperature chemistry of isolated, gas-phase molecules under strong cavity coupling to elucidate how the simplest molecular polaritons behave. These discoveries have the potential to inform practical applications for polaritonic technologies in chemistry, materials science, and quantum information science. Professor Weichman is also reforming undergraduate quantum chemistry coursework at Princeton with the goal of broadening participation in the quantum science research community and workforce. The Weichman Lab will focus on pristine gas-phase measurements wherein polariton reaction dynamics can be studied with quantum-state-specificity and without the complications of solvation. While molecular polaritons are now well established in liquids and in solid-state systems, attaining sufficiently strong light-matter interactions for gas-phase molecules has remained a challenge. The Weichman Lab accesses the regime of gas-phase strong coupling at cryogenic temperatures where molecular partition functions are small and inhomogeneous linewidths are narrow. A cryogenic buffer gas cell allows for the preparation of cold, dense molecular ensembles. This source is combined with a feedback-stabilized Fabry-Pérot optical cavity and precision laser scheme to engineer strong coupling of individual rovibrational transitions in gas-phase molecules. The Weichman Lab will harness this apparatus to investigate how benchmark chemical processes, including bimolecular reactions, photodissociation, and photoisomerization, occur under cavity coupling.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.