Uncovering Non-Adiabatic Dynamics in Strong Field Molecular Ionization

这项工作将研究电子和原子核如何在分子内部运动。观察这种运动将促进物理学家对自然界中许多过程的理解，如视觉，能量储存，能量转换和化学转化。 它对于太阳能电池、超快分子开关和量子计算机等新技术的发展也很重要。 虽然激光是操纵和测量分子中电子的天然工具，但为了真实的操纵电子，需要非常短的激光脉冲。 该项目的研究人员将使用强烈的超短激光脉冲来抑制分子，去除与分子结合的许多电子中的一个。他们将利用一种称为速度图成像的技术，在电子离开分子时拍摄电子的照片。这些照片可以用来理解电离过程中电子和原子核的耦合动力学，这对于理解化学动力学和发展高速电子学是重要的。该项目将利用成形的几个周期的激光脉冲来研究小分子（~5-10个原子）的非绝热和相关强场电离。研究人员将控制亚10 fs（3-4个光周期）激光脉冲的形状，并利用速度图成像来研究角度和动量分辨的光电子谱（与碎片离子一致）作为激光脉冲形状的函数。这将有助于更深入地了解电子如何从多轨道中移除，以及电子相关和非玻恩奥本海默动力学在电离动力学中发挥作用的程度。研究人员还将利用强场电离作为激发态动力学的探针，研究同源分子家族中的解离和内部转换，以了解相似性和差异性。该奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

This work will study how electrons and nuclei move inside of molecules. Observing such motion will advance physicists' understanding of many processes in nature such as vision, energy storage, energy conversion, and chemical transformation. It is also important for fundamental approaches to the development of new technologies such as solar cells, ultrafast molecular switches, and quantum computers. While lasers are natural tools for manipulating and measuring electrons in molecules, one requires very short laser pulses in order to manipulate electrons in real time. The investigators in this project will use intense ultrashort laser pulses in order to ionize molecules, removing one of the many electrons bound to the molecule. They will take pictures of the electrons as they come off the molecules, making use of a technique called velocity map imaging. These pictures can be used to understand the coupled dynamics of electrons and nuclei during ionization, which is important for understanding chemical dynamics and for developing high speed electronics. This project will make use of shaped few cycle laser pulses to study non-adiabatic and correlated strong field ionization of small molecules (~5-10 atoms). The investigators will control the shape of sub 10 fs (3-4 optical cycles) laser pulses, and make use of velocity map imaging in order to study the angle and momentum resolved photoelectron spectrum (in coincidence with fragment ions) as a function of laser pulse shape. This will help develop a deeper understanding of how electrons are removed from multiple orbitals, and the extent to which electron correlation and non-Born Oppenheimer dynamics play a role in the ionization dynamics. The investigators will also make use of strong field ionization as a probe of excited state dynamics, studying dissociation and internal conversion in families of homologous molecules in order to understand similarities and differences.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.