Fushitani M, Sasaki Y, Matsuda A, Fujise H, Kawabe Y, Hashigaya K, Owada S, Togashi T, Nakajima K, Yabashi M, Hikosaka Y, Hishikawa A
Department of Chemistry, Graduate School of Science, Nagoya University, Nagoya, Aichi 464-8602, Japan.
RIKEN, SPring-8 Center, Sayo, Hyogo 679-5148, Japan.
Phys Rev Lett. 2020 May 15;124(19):193201. doi: 10.1103/PhysRevLett.124.193201.
Ultrafast multiphoton ionization of Xe in strong extreme ultraviolet free-electron laser (FEL) fields (91 eV, 30 fs, 1.6×10^{12} W/cm^{2}) has been investigated by multielectron-ion coincidence spectroscopy. The electron spectra recorded in coincidence with Xe^{4+} show characteristic features associated with two-photon absorption to the 4d^{-2} double core-hole (DCH) states and subsequent Auger decay. It is found that the pathway via the DCH states, which has eluded clear identification in previous studies, makes a large contribution to the multiple ionization, despite the long FEL pulse duration compared with the lifetime of the 4d core-hole states.
利用多电子离子符合光谱技术研究了氙在强极紫外自由电子激光（FEL）场（91电子伏特，30飞秒，1.6×10¹²瓦/平方厘米）中的超快多光子电离。与Xe⁴⁺符合记录的电子能谱显示出与双光子吸收到4d⁻²双芯孔（DCH）态以及随后的俄歇衰变相关的特征。研究发现，尽管与4d芯孔态的寿命相比，FEL脉冲持续时间较长，但之前的研究中未明确识别出的通过DCH态的途径对多重电离有很大贡献。
