Understanding and Controlling Reaction Mechanisms Under Vibrational Strong Coupling

理解和控制振动强耦合下的反应机制

• 批准号: 2101988
• 负责人: Wei Xiong
• 金额: $ 50.87万
• 依托单位: University of California-San Diego
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-09-01 至 2024-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2101988&HistoricalAwards=false
• 关键词: Understanding; Controlling; Reaction; Mechanisms; Under

With support from the Chemical Structure, Dynamics, and Mechanisms-A (CSDM-A) Program in the Division of Chemistry, Wei Xiong and his group at the University of California-San Diego aim to understand the mechanisms of a specific set of chemical reactions in optical cavities. When reactants and/or products are in a cavity composed of two partial-reflective mirrors, and are highly concentrated to reach the so-called strong coupling regime, the activity and selectivity of reactions in the cavity can differ from the same reaction outside cavities. Such a phenomenon opens a new way to control chemical reactions and can profoundly impact reaction engineering through a simple optical method. However, there has been debate about the experimental observations that support the claim of cavity-modified reactions, and the molecular-level mechanisms of how the cavities modify reactions remain unclear. Dr. Xiong and his group aim to quantify the reaction in cavities and understand the underlying mechanisms through optical spectroscopy. A proper characterization of the cavity reactions and understanding of the mechanisms will lay a solid foundation for rationally designing cavities to modify chemistry. To enhance the general public's interest in chemistry, Dr. Xiong is setting up a food and chemistry YouTube channel to discuss the basic chemistry of food and cooking. Videos will feature scientists cooking food based on their own backgrounds to embrace the diverse culture in our society. While one of the purposes of this activity is to broadcast chemistry through food, something everyone can enjoy, another purpose is to show scientists in real-life settings. Observing scientists in more familiar settings can help motivate young learners to pursue STEM (science, technology, engineering and mathematics) careers and encourage their families to support such aspirations.The goal of this project is to study chemical reactions modified by molecular polaritons to gain new insight into the roles that dark modes and cooperativity play in the reactions. Vibrational strong coupling (VSC) of light and matter occurs when molecular vibrational and photon cavity modes exchange energy faster than the lifetime of both modes. Under VSC, cavity photons and molecular vibrational excitations hybridize to form molecular vibrational polaritons. Recent reports have shown several fascinating examples of how molecular potential energy landscapes and concomitant reaction pathways can be modified under VSC conditions, including modifying reaction branching ratios and enhancing or suppressing chemical reaction rates, making VSC a promising new tool to manipulate chemical reactions. However, there are several challenges in this emerging field. This project focuses on addressing three outstanding challenges by developing an alternative and more direct analytical method to quantify chemistry under VSC; quantifying the reaction performance and polariton/dark mode dynamics to understand the interplay between dark modes and polaritons and how it influences chemistry under VSC; and aiming to understand the role of energy transfer in chemistry under VSC. The main research tools include ultrafast spectroscopy and analytical instruments such as GC-MS (gas chromatography/mass spectrometry). The outcomes of this project include the development of an alternative way to quantify chemistry under VSC and better understanding of the mechanisms of chemistry under VSC. The broader impacts include new design principles for the rational design of VSC conditions to control reactions and influence the field of catalysis, pharmaceutical molecule synthesis, green chemistry, and photochemistry. The team also hosts undergraduate research students from groups that are underrepresented in science, in order to help them become familiar with graduate life and introduce them to cutting-edge research programs in an effort to broaden participation in graduate research.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.

在化学结构，动力学和机制-A（CSDM-A）计划中的支持下，Wei Xiong及其在加利福尼亚大学迭戈分校的组旨在了解光学腔中特定化学反应的机制。当反应物和/或产物在由两个部分反射镜组成的空腔中，并且高度浓缩以达到所谓的强耦合方案时，腔中反应的活性和选择性可能与相同反应的外部腔外反应不同。这种现象为控制化学反应的新方法打开了一种新的方法，并可以通过简单的光学方法深刻影响反应工程。然而，关于支持腔体修饰反应主张的实验观察的争论，以及腔体如何修饰反应的分子水平机制尚不清楚。 Xiong博士及其小组的目的是量化空腔中的反应，并通过光谱学了解潜在的机制。对机制的腔反应和理解的正确表征将为合理设计腔体修饰化学性质奠定坚实的基础。为了增强公众对化学的兴趣，Xiong博士正在建立一个食品和化学YouTube渠道，讨论食物和烹饪的基本化学反应。视频将以自己的背景来烹饪食物，以拥抱我们社会中多元化的文化。尽管这项活动的目的之一是通过食物广播化学，但每个人都可以享受的东西，另一个目的是向科学家展示现实生活中的环境。在更熟悉的环境中观察科学家可以帮助激励年轻的学习者从事STEM（科学，技术，工程和数学）职业，并鼓励其家人支持这种愿望。该项目的目的是研究分子偏振子修改的化学反应，以获得对暗模式和合作在反应中发挥作用的作用的新见解。当分子振动和光子腔模式比两种模式的寿命更快交换能量时，光和物质的振动强耦合（VSC）发生。在VSC下，腔光子和分子振动激发杂交形成了分子振动偏振子。最近的报道显示了一些令人着迷的例子，说明了如何在VSC条件下修改分子势能景观和随之而来的反应途径，包括改变反应分支比率并增强或抑制化学反应速率，从而使VSC成为操纵化学反应的新工具。但是，这个新兴领域存在一些挑战。该项目着重于通过开发一种替代性，更直接的分析方法来量化VSC下的化学反应，以应对三个杰出的挑战；量化反应性能和极化/深色模式动力学，以了解黑模式与偏振子之间的相互作用，以及它如何影响VSC下的化学反应；并旨在了解VSC下的能源转移在化学中的作用。主要的研究工具包括超快光谱和分析仪器，例如GC-MS（气相色谱/质谱法）。该项目的结果包括开发在VSC下量化化学的替代方法，以及对VSC下化学机制的更好理解。更广泛的影响包括VSC条件的合理设计的新设计原理，以控制反应并影响催化，药物分子合成，绿色化学和光化学的领域。该小组还招募了来自科学人数不足的小组的本科研究专业的学生，​​以帮助他们熟悉研究生生活，并向他们介绍尖端的研究计划，以旨在旨在扩大研究生研究的参与。该奖项反映了NSF的法定任务，并通过使用该基金会的知识优点和广泛的criperia来评估，并通过评估值得进行评估，并通过评估值得进行评估。

项目成果

Cavity-enabled enhancement of ultrafast intramolecular vibrational redistribution over pseudorotation

• DOI: 10.1126/science.add0276
• 发表时间: 2022-11-18
• 期刊: SCIENCE
• 影响因子: 56.9
• 作者: Chen, Teng-Teng;Du, Matthew;Xiong, Wei
• 通讯作者: Xiong, Wei

Molecular Vibrational Polaritons Towards Quantum Technologies

分子振动极化子走向量子技术

• DOI: 10.1002/qute.202100163
• 发表时间: 2022
• 期刊: Advanced Quantum Technologies
• 影响因子: 4.4
• 作者: Yang, Zimo;Xiong, Wei
• 通讯作者: Xiong, Wei

Molecular Vibrational Polariton Dynamics: What Can Polaritons Do?

• DOI: 10.1021/acs.accounts.2c00796
• 发表时间: 2023-04-04
• 期刊: ACCOUNTS OF CHEMICAL RESEARCH
• 影响因子: 18.3
• 作者: Xiong, Wei