Probing Multi-Electron Dynamics with Absolute Carrier-Envelope-Phase (CEP) Dependent Strong Field Interaction

一般观众摘要：原子是由相等数量的电子和原子核组成的，它们是电荷中性的。因此，他们不应该相互吸引。然而，众所周知，原子可以聚集在一起，形成生命所必需的最复杂的分子，例如蛋白质和DNA。这是因为许多电子的相关运动可以将原子粘合在一起。这被称为化学键。如果能够完全理解和控制这些运动，就可以解决许多实际问题，比如制造新的分子来治疗疾病。然而，由于化学键的多电子性质，这个问题非常复杂和具有挑战性。在这个项目中，李教授和韦恩州立大学的学生将使用一种非常强但控制良好的激光从原子和小分子中撕裂一两个电子，并观察它们如何与其余电子和激光相互作用。这是一种研究电子运动的新方法，并将提供前所未有的知识，可能导致新的化学反应控制方法。其他好处包括开发新的激光技术和培训下一代化学家和物理学家。技术观众摘要：在这个项目中，将研究多电子动力学的一个重要方面--多电子库仑势，它与离开电子的相互作用，以及这种相互作用在强场电离过程中的后果。主要的实验方法是使用高性能的离子-电子符合/协方差技术，结合少周期的近红外激光脉冲(5fs)。将充分描述少周期脉冲的特性，例如脉冲持续时间、带宽和相位。具体地说，李教授和他的学生的目标是开发一种新的技术，首次在没有理论输入的情况下确定线偏振几个周期脉冲的绝对载波包络相位(CEP)。这将为相变现象提供独立的校准。此外，与CEP相关的绝对数据，如双电离产额、电子动量分布和解离双电离的支化比，将直接与不同理论模型的结果进行比较，以揭示多电子动力学在原子和小分子体系中的重要性。这项拟议的研究利用了尖端的实验能力，将揭示复杂的多电子动力学的新信息。这项研究还将为研究强大的领域动力提供前所未有的工具。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

General audience abstract:Atoms are made of equal numbers of electrons and nuclei and they are charge neutral. Therefore, they should not attract each other. However, it is well known that atoms can group together and form the most complex molecules that are indispensable for life, e. g., proteins and DNAs. The reason for this is because the correlated motions of many electrons can glue atoms together. This is called chemical bonding. If one can fully understand and control these motions, one can solve many practical problems such as making new molecules as cures for diseases. However, because the multi-electron nature of chemical bonding, the issue is very complex and challenging to tackle. In this project Professor Li and students at Wayne State University will use a very intense but well-controlled laser to rip one or two electrons from atoms and small molecules and watch how they interact with the rest of the electrons as well as the laser. This is a new way to study electronic motions and will offer unprecedented knowledge that might lead to novel control methods of chemical reactions. Additional benefit includes developing new laser technologies and training of the next generation of chemists and physicists.Technical audience abstract:In this project an important aspect of multi-electron dynamics - the multi-electron Coulomb potential, its interactions with departing electrons and the consequences of such an interaction in strong field ionization process - will be investigated. The major experimental approach is to use high performing ion-electron coincidence/covariance techniques coupled with few-cycle near infrared laser pulses (5 fs). The properties of few-cycle pulses such as pulse duration, bandwidth and phase will be fully characterized. Specifically, Professor Li and his students aim to develop a new technique to determine the absolute carrier envelope phase (CEP) of linearly polarized few-cycle pulses for the first time without theoretical input. This will provide independent calibration of phase-dependent phenomena. Furthermore, the absolute CEP dependent data such as double ionization yields, electron momentum distributions and branching ratios of dissociative double ionization will be compared directly with the results of different theoretical modeling with and without the single active electron approximation (SAE) to reveal the importance of multi-electron dynamics in atomic and small molecular systems. The proposed research leverages cutting-edge experimental capabilities and will uncover new information on complex multi-electron dynamics. The research will also provide unprecedented tools for studying strong field dynamics.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.