Multi-dimensional Electronic Dynamics beyond the Dipole Approximation

华盛顿大学的李晓松获得了化学学部化学理论、模型和计算方法项目以及高级网络基础设施学部计算和数据支持科学与工程项目的奖励，以开发计算方法和开源软件来研究电磁场驱动下的电子动力学。受多个电磁场影响的电子过程是许多技术上重要材料功能的基础。李和他的研究小组开发的方法为促进具有理想光学特性的材料的科学发现提供了新的有力途径。该项目还为无机、理论、物理和材料化学领域的高级跨学科教育和培训提供了一种机制。该项目为参与的本科生和研究生未来在科学、工程和教育领域的职业生涯做好准备。通过结合高中和社区外展和本科生研究指导，该项目促进和促进广泛的青年参与科学和工程活动。该项目为建模时间分辨、多维电子能谱奠定了理论基础，其能量范围从光谱的紫外到x射线区域，并由脉冲之间的延迟调制，完全在第一性原理框架内。一方面，这一发展能够揭示驱动激发态化学过程/现象的物理机制，这是能源研究的基础。例如，相干激子和电荷转移动力学是一个潜在的应用。另一方面，该算法的进步极大地拓展了激发态电子结构理论在非摄动、非线性状态下的应用。在这里，我们感兴趣的过程需要对系统场相互作用的描述，它超出了电偶极子近似。这项研究活动的独特之处在于，它将时间相关的量子力学理论和光谱分析软件工具与高度并行、可扩展、可重用、社区驱动和开源的模块化高性能数值库无缝集成。研究目标是为发现和设计展示新的或增强的高阶光学、磁性、电子和等离子体特征的分子和材料提供直接途径。

Xiaosong Li of the University of Washington is supported by an award from the Chemical Theory, Models and Computational Methods program in the Chemistry Division and the Computational and Data-Enabled Science and Engineering program in the Division of Advanced Cyberinfrastructure to develop computational methods and open-source software to study the dynamics of electrons driven by electromagnetic fields. Electronic processes influenced by multiple electromagnetic fields underlie the functionality of many technologically-important materials. The methods developed by Li and his research group yield new and powerful avenues to facilitate scientific discoveries of materials that exhibit desirable optical properties. The project also provides a mechanism for advanced interdisciplinary education and training in the areas of inorganic, theoretical, physical, and materials chemistry. The project prepares participating undergraduate and graduate students for future careers in science, engineering, and education. Through a combination of high-school and community outreach and undergraduate research mentoring, this project promotes and fosters participation of a broad spectrum of youth in science and engineering activities.This project lays the theoretical groundwork for modeling time-resolved, multidimensional electronic spectroscopy, with energies ranging from the UV to X-ray regions of the spectrum and modulated by the delays between pulses, completely within the first-principles framework. On the one hand, the development is able to reveal the physical mechanisms that drive excited state chemical processes/phenomena, which is fundamental to energy research. For example, coherent excitonic and charge transfer dynamics is one potential application. On the other hand, the algorithmic advances greatly broaden the application of excited state electronic structure theory in the non-perturbative, non-linear regime. Here the process of interest requires a description of the system-field interaction that goes beyond the electric-dipole approximation. This research activity is unique in that it seamlessly integrates time-dependent quantum mechanical theories and spectral analysis software tools with modular high-performance numerical libraries that are highly parallelized, extensible, reusable, community-driven, and open-sourced. The research goals are to provide a direct path to the discovery and design of molecules and materials that demonstrate new or enhanced high-order optical, magnetic, electronic, and plasmonic features.