Next Generation Experiment and Theory for Photoelectron Spectroscopy

我们对分子结构和化学键性质的理解与我们测量控制化学键的外层电子（价电子）特征的能力同步发展。光电子能谱是这一发展过程中的一个关键工具，它通过高能量的光爆发将一个电子从分子中移除。通过测量出电子的能量和它运动的方向，我们可以得到分子中电子和原子核排列的详细信息。化学是非常动态的，原子和分子在不断运动，化学反应是由结构和键的相关变化决定的。实时测量化学动力学，从反应物到产物，是具有挑战性的，并且需要能够解决负责化学键的价电子排列变化的探针。利用超短脉冲光，我们可以进行具有足够时间分辨率的光电子能谱测量，以跟踪反应过程中分子电子结构的动态变化。我们将使用新的光源和先进的理论，提供详细的测量和分析光致化学动力学。该实验将利用基于高谐波产生的光源和高强度激光来监测光化学反应中所有重要的结构。理论的发展将结合最先进的量子分子动力学模拟和高精度计算光电子能谱的新方法，允许从实验数据中提取准确的图像，以实现化学反应的详细映射。这项研究将有助于更好地理解控制光化学反应结果的驱动力，并为控制、设计和指导化学反应提供新方法。

Our understanding of the structure of molecules and the nature of the chemical bond has developed in tandem with our ability to measure the characteristics of the outer (valence) electrons that control chemical bonding. A key tool in this development has been photoelectron spectroscopy, whereby a high-energy burst of light removes an electron from the molecule. By measuring the energy of the outgoing electron and the direction in which it travels, we can obtain detailed information on the arrangement of the electrons and the nuclei in the molecule. Chemistry is very dynamic, with atoms and molecules in constant motion and chemical reactions defined by associated changes in structure and bonding. Measuring chemical dynamics in real time, from reactants to products, is challenging and requires probes capable of resolving the changes in the arrangement of the valence electrons responsible for chemical bonding. Using ultrashort pulses of light, we can make photoelectron spectroscopy measurements with sufficient time-resolution to track the dynamic changes in the molecular electronic structure during reactions. We will use new light sources and advanced theory to provide detailed measurements and analysis of light-induced chemical dynamics. The experiments will take advantage of high harmonic generation based light sources and high intensity lasers to monitor all of the structures important during photochemical reactions. The theory developments will combine state-of-the-art simulations of quantum molecular dynamics with new methods to calculate photoelectron spectra with high accuracy, allowing accurate images to be extracted from the experimental data to achieve a detailed mapping of the chemical reactions. This research will enable better understanding of the driving forces that control the outcomes of photochemical reactions and allow new methods to control, design, and direct chemical reactivity.