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

普通观众摘要：原子是由相同数量的电子和原子核组成的，它们是电中性的。因此，它们不应该相互吸引。然而，众所周知，原子可以聚集在一起，形成生命所不可缺少的最复杂的分子。例如，在一个实施例中，蛋白质和DNA。其原因是许多电子的相关运动可以将原子粘合在一起。这就是所谓的化学键。如果人们能够完全理解和控制这些运动，就可以解决许多实际问题，例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，难以解决。在这个项目中，李教授和韦恩州立大学的学生们将使用一种非常强烈但控制良好的激光，从原子和小分子中剥离一两个电子，并观察它们如何与其余电子以及激光相互作用。这是一种研究电子运动的新方法，将提供前所未有的知识，可能导致化学反应的新控制方法。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，它与离开的电子的相互作用，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，加上几个周期的近红外激光脉冲（5 fs）。几个周期的脉冲，如脉冲持续时间，带宽和相位的属性将得到充分的表征。具体而言，李教授和他的学生旨在开发一种新技术，首次在没有理论输入的情况下确定线偏振少周期脉冲的绝对载波包络相位（CEP）。这将提供相位相关现象的独立校准。此外，绝对CEP依赖的数据，如双电离产额，电子动量分布和解离双电离的分支比将直接与不同的理论模型的结果进行比较，有和没有单活性电子近似（SAE），以揭示多电子动力学在原子和小分子系统的重要性。拟议的研究利用了尖端的实验能力，并将揭示有关复杂多电子动力学的新信息。该研究还将为研究强场动力学提供前所未有的工具。该奖项反映了NSF的法定使命，并被认为值得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来支持。

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.