CAREER: Unraveling Chemical Consequences of Non-adiabatic Energy Transfer at the Gas-Surface Interface

田纳西大学的Sharani Roy获得了化学学部化学理论、模型和计算方法项目的CAREER奖，从理论上研究了气体表面界面化学过程中非绝热能量传递的作用。固体表面和界面的化学是多种技术的基础，从多相催化、气体储存和化学传感，到纳米电子学、纳米光刻和太阳能电池。它还支配着自然现象，如腐蚀和氧化过程，例如铁的生锈和岩石的风化。甚至星际分子的形成也发生在尘埃颗粒的表面。在上述所有例子中，控制过程的基本相互作用是气体表面相互作用。每一个复杂的表面过程都是由一系列基本步骤组成的，如气体原子和分子在固体表面上的散射、吸附、扩散、解吸和反应。因此，详细了解气-表面界面对于解释这种不同的表面过程至关重要。Roy小组研究了不同表面和界面现象下的基本气体表面相互作用，重点研究了涉及核运动和电子运动之间强耦合的现象。这种耦合可以对表面化学过程的速率和途径产生重要的和意想不到的后果。Roy博士的研究与多组件教育计划相结合，该计划包括在科学计算背景下开发计算化学，表面化学和高性能计算课程。此外，罗伊博士计划与橡树岭国家实验室合作组织一个关于表面化学反应和动力学的研讨会。表面和界面化学的理论和计算研究通常涉及化学动力学的研究，其中原子和分子在表面上的运动是用经典力学模拟的。分子动力学（MD）模拟的概念在描述气体表面相互作用方面非常成功，并为复杂的表面过程提供了有价值的定性见解。传统的MD依赖于普遍存在的玻恩-奥本海默近似或绝热近似，它假设核运动与电子运动不耦合。然而，有几个基本的和工业上重要的气体表面系统，这种近似不成立。因此，开发准确有效的动力学方法来理解绝热近似弱或无效的界面化学过程是至关重要的。Roy博士的目标是进一步发展金属表面非绝热动力学的“表面跳跃”理论方法，并将其应用于研究电子和原子核之间有效转移能量的强非绝热气体表面现象。这些现象包括(a)氢原子与金表面的相互作用，(b)氧原子与银表面的相互作用，以及(c)分子结中的非弹性电子传递。总体目标是开发一种更广泛适用于表面和界面化学的方法，这将有助于获得比Born-Oppenheimer近似更全面的动力学理解。

Sharani Roy of the University of Tennessee is supported by a CAREER award from the Chemical Theory, Models and Computational Methods program in the Chemistry Division to theoretically investigate the role of nonadiabatic energy transfer in chemical processes at the gas-surface interface. Chemistry at solid surfaces and interfaces is the foundation of a wide range of technologies ranging from heterogeneous catalysis, gas storage, and chemical sensing, to nanoelectronics, nanolithography, and solar cells. It also governs natural phenomena, such as corrosion and oxidation processes, e.g., the rusting of iron and the weathering of rocks. Even interstellar formation of molecules occurs on the surfaces of dust particles. In all the above examples, the fundamental interactions that govern the processes are gas-surface interactions. Each complex surface process is comprised of a series of elementary steps, such as the scattering, adsorption, diffusion, desorption, and reactions of gaseous atoms and molecules on solid surfaces. Therefore, a detailed understanding of the gas-surface interface is essential to explain such diverse surface processes. The Roy group investigates fundamental gas-surface interactions underlying different surface and interface phenomena, with focus on phenomena that involve strong coupling between nuclear motion and electronic motion. This coupling can have important and unexpected consequences on the rates and pathways of chemical processes at surfaces. Dr. Roy's research is integrated with a multi-component education plan that includes the development of courses on computational chemistry, surface chemistry, and high-performance computing in the context of scientific computing. In addition, Dr. Roy plans to organize a symposium on chemical reactions and dynamics at surfaces in collaboration with the Oak Ridge National Laboratory.Theoretical and computational research in surface and interface chemistry often involves studies of chemical dynamics in which the motion of atoms and molecules on surfaces is simulated using classical mechanics. This concept of molecular dynamics (MD) simulations has been very successful in describing gas-surface interactions, and has provided valuable qualitative insight into complicated surface processes. Conventional MD relies on the ubiquitous Born-Oppenheimer or adiabatic approximation, which assumes that nuclear motion is uncoupled from electronic motion. However, there are several fundamentally and industrially important gas-surface systems in which this approximation breaks down. Therefore, it is critical to develop accurate and efficient dynamics methods that can be applied to understand interfacial chemical processes where the adiabatic approximation is weak or invalid. Dr. Roy aims to further develop the 'surface hopping' theoretical method of nonadiabatic dynamics in the context of metal surfaces, and apply it to study strongly nonadiabatic gas-surface phenomena where energy is efficiently transferred between electrons and nuclei. These phenomena include (a) the interaction of hydrogen atoms with a gold surface, (b) the interaction of oxygen atoms with a silver surface, and (c) inelastic electron transport in molecular junctions. The overall goal is to develop a method with broader applicability to surface and interface chemistry that will help to attain a more comprehensive understanding of dynamics beyond the Born-Oppenheimer approximation.