Attosecond and Strong Field Physics in Correlated Multielectron System

阿秒光脉冲产生的惊人进展，以及近红外区高强度激光的可用性，为复杂系统中实时电子动力学的研究开辟了新的可能性。阿秒和强场物理学的目标之一是在其自然时间尺度上访问关于电子运动的基本信息，并且能够控制分子中的电荷迁移，例如，来选择在分子位点上的特定键断裂，或者触发化学反应。该项目的主要目标是开发一种新的，高效的，通用的数值方法，以支持多电子系统与超短和强激光脉冲相互作用的实验和理论研究。本工作旨在为阿秒化学的发展做出贡献，并最终弥合阿秒物理与生物学之间的差距。此外，由于将实验测量与实时有意义的物理观测值联系起来远非简单，因此将研究新的方法来跟踪从分子中的不同价层发射的光电子的快速动态，以及在强激光场中的隧道电离期间。随着阿秒物理学成为最繁荣的科学领域之一，需要新的理论工具来支持复杂系统中阿秒现象的探索。ATTOMESA是一种新的超快物理数值方法，将被设计用于处理各种多光子过程，并研究原子和分子中驱动多电子阿秒和强场动力学的未探索方面。在ATTOMESA中使用的形式主义包括电子相关和交换，以及通道间耦合。它是基于一个混合的正交方法，其中使用高斯型轨道的量子化学描述中使用的短程到中程电子-分子相互作用区域，而有限元离散变量表示函数的补充说明在较大的电子半径，导致一个高效的并行从头计算方法能够处理强场过程中的分子。因此，高次谐波产生和受抑隧道电离等过程可以完全从头开始处理。在这项工作中，以下物理过程将与ATTOMESA处理;附近的库珀最小值和不同的价壳层之间的光电离时间延迟，使用一种新的光谱方法，在生物分子中的电子相干性突然光电离后的估计，并最终评估电子相关的条纹/attocock实验中的作用。最后，玻姆力学将被用作解释原子中强场现象的有用工具。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The astonishing advances in the generation of attosecond light pulses, and the availability of high-intensity lasers in the near-infrared region, have opened up a field of new possibilities in the study of the real-time electron dynamics in complex systems. One of the goals of attosecond and strong-field physics is to access fundamental information on electronic motion in its natural time scale and be able to control charge migration in molecules, e.g., to select a specific bond breaking at a molecular site, or to trigger a chemical reaction. The main objective of the project is to develop a new, efficient, and versatile numerical method to support the experimental and theoretical study of the interaction of multi-electron systems with ultra-short and intense laser pulses. This work aims at contributing to the development of attochemistry and ultimately bridge the gap between attosecond physics and biology. In addition, as connecting experimental measurements to real-time meaningful physical observables has shown to be far from simple, new methods will be investigated to track the rapid dynamics of photoelectron emitted from different valence shells in molecules, as well as during tunnel ionization in intense laser fields. With attosecond physics becoming among the most thriving fields of science, new theoretical tools are needed to support the exploration of attosecond phenomena in complex systems. ATTOMESA, a new numerical method for ultrafast physics, will be designed to treat various multiphoton processes investigated with current experimental setups, and to study unexplored aspects of driven multielectron attosecond and strong field dynamics in atoms and molecules. The formalism used in ATTOMESA includes electron correlation and exchange, as well as inter-channel coupling. It is based on a hybrid quadrature approach, where a quantum-chemistry description using Gaussian-type orbitals is used in the short-range to mid-range electron-molecule interaction region, while finite-element discretized variable representation functions complement the description at larger electronic radius, resulting in a highly efficient parallel ab initio method able to treat strong field processes in molecules. Consequently, processes such as high-harmonic generation and frustrated tunnel ionization can be handled fully ab initio. In this work, the following physical processes will be treated with ATTOMESA; photoionization time delay near a Cooper minimum and between different valence shells using a new spectroscopic method, estimation of electronic coherence in a biomolecule after sudden photoionization, and finally assessing the role of electron correlation in streaking/attoclock experiments. Finally, Bohmian mechanics will be employed as a useful tool to interpret strong-field phenomena in atoms.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.