Soft-x-rayM2,3absorption spectra of some transition-metal halides

The soft-x-ray $M_{2,3}$ absorption spectra due to excitation of $3p$ electrons of transition metals, Cr, Mn, Fe, Co, and Ni, and the metal ions in the halides, Cr${\mathrm{Cl}}_2$, Cr${\mathrm{Br}}_3$, Mn${\mathrm{F}}_2$, Mn${\mathrm{Cl}}_2$, Mn${\mathrm{Br}}_2$, Fe${\mathrm{Cl}}_2$, Fe${\mathrm{Br}}_2$, Co${\mathrm{F}}_2$, Co${\mathrm{Cl}}_2$, Co${\mathrm{Br}}_2$, Ni${\mathrm{Cl}}_2$, and Ni${\mathrm{Br}}_2$, are obtained at room temperature. Synchrotron orbital radiation from a 1.3-GeV electron synchrotron at the Institute for Nuclear Study in Tokyo is used as a light source. The fine structures of the spectra are observed on the low-energy side of the absorption threshold of all the transition-metal halides except for nickel halides. These structures suggest the existence of the localized $d$ levels which lie a few eV below a $4s$ band.