准直分子双色场致电子衍射与亚飞秒结构演变信息获取

Laser-induced electron diffraction is an important method for ultra-fast extablishing the structure of the molecule, the core issue of this research method is the extraction of electron-molecular ion elastic differential scattering cross sections and the information of ultra-fast molecular structural dynamics. This project will combine molecular alignment and photoelectron velocity map imaging techniques, aiming to explore the ultra-fast evolution information of molecular structure based on the electron diffraction and self-imaging mechanism during the interaction between molecule and alternative two-color laser field, to study the time-resolved molecular dynamics by using a relative phase adjustable two-color laser field. In this project, we will experimentally measure the laser-induced rescattering electron spectroscopy of the highly aligned molecules which are obtained by the combination of rotational state-selection and non-adiabatic alignment techniques. By using two-color field with different relative phase (corresponding to different electron returning time to the core) to induce the electron diffraction imaging, then conbine the quantitative rescattering theory and independent atom model, we can extract the electron-ion elastic differential scattering cross sections and the bond length of molecular component atom, especially on the study of sub-femtosecond time-resolved molecular dynamics.

激光场致电子衍射是超快探测分子结构的重要方法，该研究方法的核心问题是电子-分子离子弹性散射的微分散射截面以及超快分子结构动力学信息的获取。本项目将结合分子准直与光电子速度成像技术，旨在深入探索分子坐标系下双色激光场致电离电子在交变激光场作用下回核发生衍射“自成像”过程所携带的超快分子结构演变信息，并以利用相对相位可调的双色激光场探测分子组成原子键长的时间分辨动力学过程作为研究方案。项目拟实验测量一系列通过转动态选择结合非绝热准直技术获得的高度准直分子的激光场致重散射电子动量谱，利用双色场在不同相对相位（对应不同的电子回核时间）下诱导电子衍射成像，并结合定量重散射理论以及独立原子模型等理论分析，实现对于电子-离子弹性散射的微分散射截面和分子组成原子间键长的提取，特别是针对亚飞秒时间分辨下的分子结构动力学过程进行研究。