Spatio-Temporal and Site-Specific Chemical Dynamics at Interfaces

在这项由化学结构、动力学和机理资助的项目中，芝加哥大学的Steven J.Sibener教授解决了表面反应动力学中的几个关键问题，导致了对分子界面反应性的基本理解的进展。这一科学计划对先进材料的制备、多相催化、燃烧和保护性薄膜涂层的设计具有直接的影响。本项目侧重于表面化学动力学，包括特定位置的反应性，绝热和非绝热的气体-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，定向控制的沉积和薄膜生长，以及几何约束和立体特定的反应研究，在这些反应中，高能原子物种与由于成键和薄膜结构的性质而预先排列的分子发生反应。这是利用超音速分子束、扫描隧道/原子力显微镜和表面光谱仪的组合来完成的。通过与理论和数值模拟的比较，对计算出的反应势能面和反应机理路径进行了精度检验。反应界面的直接可视化有助于揭示特定部位的反应性和作为局部结构和反应程度的函数的时空相关性。在这些研究中，应用了对试剂能量、入射角、强度和量子态的精确控制。研究了非平衡条件下的界面化学。通过接触当地少数族裔社区，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，这些活动在芝加哥南部代表性不足的人口中具有相当大的代表性。

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.