Spatio-Temporal and Site-Specific Chemical Dynamics at Interfaces

芝加哥大学的Steven J. Sibener教授在化学部化学结构、动力学和机理A项目资助的这个项目中，解决了表面反应动力学中的几个关键问题，从而在对界面分子反应性的基本理解方面取得了进展。这个科学项目对先进材料的制造、多相催化、燃烧和保护薄膜涂层的设计有直接的影响。该项目侧重于表面化学动力学，包括位点特异性反应性、绝热和非绝热气体表面相互作用，如解离化学吸附，包括能量耗散和表面迁移率、定向控制沉积和薄膜生长，以及几何约束和立体特异性反应研究，在这些反应中，高能原子物种与由于其键合和薄膜结构的性质而预先排列的分子发生反应。这是通过超音速分子束、扫描隧道/原子力显微镜和表面光谱的结合来完成的。通过与理论和数值模拟的比较，对计算得到的反应势能面和反应机理路径进行了精确的验证。反应界面的直接可视化有助于揭示特定位点的反应性和时空相关性作为局部结构和反应程度的函数。在这些研究中，对试剂能量、入射角、强度和量子态进行精确控制。界面化学在非平衡条件下进行了研究。通过与当地少数民族社区的接触，包括当地公立、特许和私立学校，以及博物馆科学活动，产生了更广泛的社会影响，这些活动有大量来自芝加哥南部人口的代表性不足。

In this project funded by the Chemical Structure, Dynamics and Mechanisms A program of the Chemistry Division, Professor Steven J. Sibener of The University of Chicago addresses several key issues in surface reaction dynamics, leading to advances in the fundamental understanding of molecular reactivity at interfaces. This scientific program has direct implications for advanced materials fabrication, heterogeneous catalysis, combustion, and the design of protective thin film coatings.This project focuses on 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, 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. This is being accomplished using a combination of supersonic molecular beams, scanning tunneling/atomic force microscopy, and surface spectroscopies. Comparisons with theory and numerical simulations provide precision tests of calculated reaction potential energy surfaces and mechanistic reaction pathways. Direct visualization of reacting interfaces helps to reveal site-specific reactivity and spatio-temporal correlations as a function of local structure and reaction extent. In these studies, precise control over reagent energy, incident angle, intensity, and quantum state are applied. Interfacial chemistry is examined under non-equilibrium conditions. Societal broader impact occurs via outreach to the local minority community, including local public, charter, and private schools, and museum science activities that have substantial representation from underrepresented south-side Chicago populations.