锕系元素（如钍和铀等）其未充满的5f与6d电子壳层参与化合物成键，由于重元素的强相对论效应以及复杂的电子相关效应，使得其原子和化合物电子结构十分复杂。负离子光电子能谱能直接获取锕系化合物的价层电子结构信息，这些数据有助于在原子和分子水平上揭示锕系化合物的化学性质和化学键。本项目利用新一代高分辨光电子速度成像技术（VMI）研究若干锕系化合物体系的电子结构和化学键。负离子光电子能谱也是测量分子电子亲和势（EA）的最有效手段之一，此外从负离子上剥离电子而获取的光电子能谱图是终态分子的低能电子激发态信息，精确的实验数据能够用于检验现有的锕系元素理论化学。VMI相比于传统的光电子能谱，还能得到激光剥离的电子空间角分布信息，由于激光剥离过程涉及电子从分子的价键轨道移出，所以能直接探测锕系5f或6d轨道参与化学成键的信息。本项目的实施也为先进核燃料循环和乏燃料化学分离研究提供锕系元素化学基础研究支撑。

Actinide elements (such as Thorium and Uranium) with partially filled 5f and 6d electron can participate chemical bonding, which form vary complicated electronic structures because of the strong relativistic effect and electron correlation effect. Anion photoelectron spectroscopy can directly probing the electronic structures of valence electron shell and the chemical bondings, which can help to reveal the fundamental actinide chemical properties and bonding at molecular (or atomic) level. This project focus on probing the electronic structures and chemical bondings of actinide species by newly designed high resolution photoelectron velocity map imaging (VMI). Anion photoelectron spectroscopy is also the most powerful technique to obtain molecular electron affinity (EA), furthermore, the spectra recorded from photodetachment of anions contain the information of the final neutral state, and accurate experimental data provide test bed to verify actinide theoretical method. VMI technique can provide extra angular distribution information of photodetached electron by linear polarized laser; photodetachment involves removal of electrons from occupied valence molecular orbitals and can probe directly the participation in chemical bonding by the 5f or 6d orbitals of actinide elements.