Eu原子4f76p3/26d自电离过程的动力学特性
Dynamic properties of Eu 4f76p3/26d autoionizing states

采用孤立实激发技术(isolated-core excitation, ICE)及速度影像技术(velocity-map imaging，VMI)，研究了Eu原子4f76p3/26d自电离过程的动力学特性。孤立实激发技术用于将Eu原子从基态4f76s2 8S7/2经中间态4f76s6p激发到4f76s6d里德堡态，然后将其进一步激发至4f76p3/26d自电离态; 速度影像技术用于探测其自电离过程的动力学特性，从而获得自电离衰变的分支比(branch ratio, BR)和弹射电子的角分布(angular distribution, AD)。自电离衰变的分支比代表离子的能量分布，从中获得VMI影像的径向信息；而通过各向异性参数描述的弹射电子的角分布揭示了VMI影像的角向信息。此外，讨论了自电离衰变分支比和弹射电子角分布在整个自电离共振能域内的变化情况。基于4f76s+ 和 4f75d+两个离子态的分支比，讨论了实现Eu离子粒子数反转的可能性。
The dynamic properties of Eu 4f76p3/26d autoionizing states are studied systematically with the isolated-core excitation(ICE) and the velocity-map imaging (VMI) techniques. The ICE technique is utilized to excite the Eu atom from the 4f76s2 8S7/2 ground state to the 4f76s6d Rydberg state via the 4f76s6p intermediate state, then excited to the 4f76p3/26d autoionizing states, while the VMI technique is used to detect the dynamic process of autoionization, from which the branching ratio (BR) of ions and the angular distribution (AD) of ejected electrons from Eu 4f76p3/26d autoionizing states are achieved. The BR represents energy distribution of ions, by observing the radical information of the VMI image, while the AD, characterized by anisotropy parameters, reveals the differential cross section of autoionization extracted from the angular information of the VMI image. Furthermore, the variation of the BR and AD are analyzed within the entire region of autoionization resonance. Based on the results of BR between 4f76s+ and 4f75d+ ionic states, the possibility of the population inversion is discussed.