Bulk-sensitive X-ray polarization dependent valence band photoelectron spectra of the 4d transition metals (TMs) of Y, Zr, Nb, Mo, Ru, Rh, Pd, and Ag were measured with hard X-ray photoelectron spectroscopy (HAXPES). The valence band spectral shapes of 4d TMs were modified by the X-ray polarization, but the changes of the spectral shapes of the 4d TMs were smaller than those of the 3d TMs [S. Ueda and I. Hamada, J. Phys. Soc. Jpn. 86, 124706 (2017)]. We simulated the HAXPES spectra, which correspond to the cross-section weighted densities of states (DOSs), where the 4d, 5s, and 5p partial DOSs were obtained by the density functional theory calculations. By comparing the polarization dependent experimental and simulated HAXPES spectra, the relative photoionization cross-sections of the 5s and 5p orbitals to the 4d orbital were determined. The simulated HAXPES spectra reproduced well the tendency of the experimental spectra for the 4d TMs, in contrast to the case of 3d TMs, in which the 3d–3d electron correlation plays an important role in the electronic structures. This result indicates that the 4d states are delocalized and the electron correlation is very weak in the 4d TMs.

中文翻译：

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偏振相关的体敏价带光电发射光谱和密度泛函理论计算：第二部分。4d过渡金属

Y，Zr，Nb，Mo，Ru，Rh，Pd和Ag的4 d过渡金属（TM）的体敏X射线偏振依赖性价带光电子能谱用硬X射线光电子能谱（HAXPES）测量。X射线极化修饰了4 d TM的价带光谱形状，但4 d TM的光谱形状的变化小于3 d TM的[S。Ueda和I. Hamada，J。Phys。Soc。日本。86，124706（2017）]。我们模拟了HAXPES光谱，该光谱对应于4 d，5 s和5 p的横截面加权状态密度（DOS）。通过密度泛函理论计算获得了部分DOS。通过比较偏振相关的实验和模拟的HAXPES光谱，可以确定5 s和5 p轨道相对于4 d轨道的相对光电离截面。与3 d TM的情况相反，其中3 d –3 d电子相关在电子结构中起重要作用的情况下，模拟的HAXPES光谱很好地再现了4 d TM的实验光谱趋势。该结果表明，在4 d TM中，4 d态离域并且电子相关性非常弱。