Theoretical Investigation of Strong Field Processes for Advancing Attosecond Chemistry

这项研究研究原子或分子的电子对强激光场和彼此之间的反应。强激光场用于研究阿秒（10^-18 s）时间尺度下的电子动力学，用于太阳能转换和光合作用等应用。以前的研究假设在这些系统中只有一个电子是活跃的。然而，现在的实验表明，许多电子之间的相互作用和与场的相互作用必须包括在内。本项目将尝试包括这些影响。此外，该项目将为两名本科生和一名研究生提供广泛的理论和计算训练。作为项目的一部分，产生阿秒化学有用信息的计算将被纳入本科高级物理化学课程。与参与该项目的实验家和量子化学家的合作将有助于建立传统光谱学与新兴阿秒化学之间的联系。本研究的重点是过渡金属原子钒、镍、铌、钯和钽在强激光场中的抑制电离，以及氩、氮和分子NO的高谐波产生（HHG）的光谱特征。其特征包括库珀极小值和共振增强的HHG。将有广泛的基准测试，包括与已发表的结果和不同条件之间的比较，这将提供对时间相关密度泛函理论（TDDFT）方法和改进方法的见解。提出的研究将给出最可能的离子状态，出射电子波函数的形式，以及随时间变化的交换势和相关势。这些知识将导致对强场多电子动力学的新的理解和改进的建模。

This research studies how electrons of an atom or molecule react to intense laser fields and to each other. Strong laser fields are used to study electron dynamics at the attosecond (10^-18 s) timescale for applications such as solar energy conversion and photosynthesis. Previous studies have assumed that only one electron is active in these systems. However, experiments have now shown that the interaction of many electrons, both with each other and with the field must be included. This project will attempt to include these effects. In addition, this project will provide two undergraduate students and one graduate student a broad array of theoretical and computational training. As part of the project, computations that yield useful information on attosecond chemistry will be incorporated into the curriculum for the undergraduate advanced physical chemistry class. Collaborations with experimentalists and quantum chemists involved in the project will contribute to building the connection between conventional spectroscopy and the emerging attosecond chemistry.The focus of this investigation will be the suppressed ionization of transition metal atoms vanadium, nickel, niobium, palladium, and tantalum in intense laser fields, and spectral features of high harmonic generation (HHG) for argon, nitrogen, and the molecule NO. The features include Cooper minima and HHG enhanced by resonances. There will be extensive benchmarking that consists of comparisons with published results and among different conditions, which will provide insight into the time-dependent density functional theory (TDDFT) approach and methods to improve it as well. The proposed study will render the most probable ion state, the form of the out-going electron wave function, and the time-dependent exchange and correlation potentials. This knowledge will lead to new understanding and improved modeling of strong field many-electron dynamics.