Atomic-level Imaging and Molecular Beam Scattering Studies of Interfacial Chemical Dynamics

界面化学动力学的原子级成像和分子束散射研究

• 批准号: 2313365
• 负责人: Steven Sibener
• 金额: $ 52.5万
• 依托单位: University of Chicago
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-07-01 至 2026-06-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2313365&HistoricalAwards=false
• 关键词: Atomic; level; Imaging; Molecular; Beam

With support from the Chemical Structure, Dynamics, and Mechanisms-A (CSDM-A) program in the Division of Chemistry, Professor Steven Sibener of the University of Chicago is studying chemical reactions that occur when molecules collide with surfaces. Understanding these gas-surface reactions is challenging, since the likelihood of reaction depends on the speed and angle that molecules strike the surface, and these are difficult to control. Further complicating matters, when surfaces are viewed up close, they exhibit many atomic-scale structures, including steps, missing atoms, and islands, each of which can exhibit different reactivity. Professor Sibener and his students will use molecular beams to control the collision with the surface and then visualize how molecules attach to, react, and depart from the interface. Their discoveries could reveal the underlying mechanisms that govern chemical reactivity in a host of emerging technologies, including the design and development of new functional materials for sustainable chemistry and quantum information science applications. The project will also contribute to the development of the Nation's science, technology, engineering, and mathematics (STEM) workforce by providing research opportunities for undergraduate students, graduate students, and postdoctoral scholars, as well as outreach activities involving local schools and Chicago’s Museum of Science and Industry. This project will examine issues in surface chemical dynamics that include site specific reactivity, adiabatic and non-adiabatic gas-surface interactions such as dissociative chemisorption including energy dissipation and surface mobility, directionally-controlled deposition and film growth, thin film reactivity, and geometry-constrained and stereo-specific reaction studies in which energetic atomic species react with molecules that are pre-aligned due to the nature of their bonding and film structure. Reactants will be pre-aligned using either oriented surface adsorption or pre-ordered reactive end-groups on self-assembled monolayers, thus presenting sterically controlled reaction partners to incident gas phase reagents. This will allow systematic exploration of molecular reactivity and reaction pathways using defined entrance channel reaction conditions including well-defined energy and polar/azimuthal angles of attack with respect to the molecular framework. Comparisons with dissociative chemisorption and reactive scattering calculations, done in conjunction with quantum theory and molecular dynamics simulations, will lead to precision tests of calculated reaction potential energy surfaces and mechanistic reaction pathways. Control of reagent energy, incident angle, intensity, and quantum state will enable the examination of interfacial chemistry under non-equilibrium energetic conditions.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，芝加哥大学的史蒂文·西伯纳教授正在研究分子与表面碰撞时发生的化学反应。理解这些气体表面反应是具有挑战性的，因为反应的可能性取决于分子撞击表面的速度和角度，而这些速度和角度很难控制。更复杂的事情是，当近距离观察表面时，它们表现出许多原子尺度结构，包括台阶，缺失原子和岛屿，每个结构都会表现出不同的反应性。 Sibener教授和他的学生将使用分子梁来控制与表面的碰撞，然后可视化分子如何与界面相连，反应和部分。他们的发现可以揭示在许多新兴技术中控制化学反应性的潜在机制，包括设计和开发可持续化学和量子信息科学应用的新功能材料。该项目还将通过为本科生，研究生和博士后学者以及涉及当地学校和芝加哥科学博物馆和工业博物馆的外展活动提供研究机会，从而为国家科学，技术，工程和数学（STEM）劳动力的发展做出贡献。该项目将在表面化学动力学中检查问题，这些动力学包括特定的反应性，绝热性和绝热气体表面相互作用，例如解离化学吸附，包括能量耗散和表面迁移率，方向控制的沉积和薄膜的生长，薄膜反应性以及几何反应性以及几何形状的反应性以及与他们的构成型物种的构成和构成的反应，该物种与构成构成的构成对构成的反应，这些反应是对构成的构成，这些反应是对构成的构成，这些反应是对构成的构成，这些反应是对构成的构成，这些反应是对构成的构成，这些反应是对构成的构成，这些反应是对构成的构成。 结构。反应物将使用定向的表面吸附或在自组装单层上进行的反应反应性终端组进行预一致，从而对入射气相试剂呈现立体控制的反应伙伴。这将允许使用定义的入口通道反应条件进行系统的探索分子反应性和反应途径，包括相对于分子框架的良好定义的能量和极性/方位角攻击角度。与量子理论和分子动力学模拟结合进行的解离化学吸附和反应性散射计算的比较将导致对计算的反应势能表面和机械反应途径进行精确测试。控制试剂能量，入射角，强度和量子状态将在非平衡能量条件下检查界面化学。该奖项反映了NSF的法定任务，并被认为是值得通过基金会的智力优点和更广泛影响的评估来通过评估来支持的。