Zhong Shiyang, Vinbladh Jimmy, Busto David, Squibb Richard J, Isinger Marcus, Neoričić Lana, Laurell Hugo, Weissenbilder Robin, Arnold Cord L, Feifel Raimund, Dahlström Jan Marcus, Wendin Göran, Gisselbrecht Mathieu, Lindroth Eva, L'Huillier Anne
Department of Physics, Lund University, P.O. Box 118, Lund, SE-221 00, Sweden.
Department of Physics, Stockholm University, AlbaNova University Center, Stockholm, SE-106 91, Sweden.
Nat Commun. 2020 Oct 7;11(1):5042. doi: 10.1038/s41467-020-18847-1.
The photoionization of xenon atoms in the 70-100 eV range reveals several fascinating physical phenomena such as a giant resonance induced by the dynamic rearrangement of the electron cloud after photon absorption, an anomalous branching ratio between intermediate Xe states separated by the spin-orbit interaction and multiple Auger decay processes. These phenomena have been studied in the past, using in particular synchrotron radiation, but without access to real-time dynamics. Here, we study the dynamics of Xe 4d photoionization on its natural time scale combining attosecond interferometry and coincidence spectroscopy. A time-frequency analysis of the involved transitions allows us to identify two interfering ionization mechanisms: the broad giant dipole resonance with a fast decay time less than 50 as, and a narrow resonance at threshold induced by spin-flip transitions, with much longer decay times of several hundred as. Our results provide insight into the complex electron-spin dynamics of photo-induced phenomena.
氙原子在70 - 100电子伏特范围内的光电离揭示了几种迷人的物理现象，比如光子吸收后电子云动态重排引发的巨共振、由自旋轨道相互作用分隔的中间氙态之间的反常分支比以及多个俄歇衰变过程。过去已经对这些现象进行了研究，特别是利用同步辐射，但无法获取实时动力学信息。在此，我们结合阿秒干涉测量法和符合光谱学，在其自然时间尺度上研究氙4d光电离的动力学。对所涉及跃迁的时频分析使我们能够识别两种干涉电离机制：具有小于50阿秒快速衰减时间的宽巨偶极共振，以及由自旋翻转跃迁在阈值处诱导产生的窄共振，其衰减时间长得多，达几百阿秒。我们的结果为光致现象的复杂电子自旋动力学提供了深入理解。
