X-RAY SPECTROSCOPIC PROPERTIES AND ELECTRONIC STRUCTURE OF Ca3Ga2Ge4O14.

We have obtained X-ray emission spectra of Ga and Ge in Ca₃Ga₂Ge₄O₁₄, X-ray emission OKα-spectra in Ca₃Ga₂Ge₄O₁₄, Ca₃Ga₂Ge₄O₁₄ + Ce3%, and Ca₃Ga₂Ge₄O₁₄ + Eu4% and Xray photoelectron spectra in Ca₃Ga₂Ge₄O₁₄ . Our X-ray spectral studies of the Ca₃Ga₂Ge₄O₁₄ gallogermanate have shown that the top of the valence band near the Fermi level is formed mainly by p states of gallium and germanium as well as p states of oxygen, whose intensity is sufficiently low. The middle of the valence band is formed by gallium 3d states with oxygen 2s states lying below them. These states are hybridized with 4p states of gallium and germanium because of which there are Kβ′′-satellites in the Kβ₂-subbands of gallium and germanium. The bottom of the valence band is formed by 3d states of germanium, whose contribution to chemical bonding is insignificant. The X-ray emission bands of Ga and Ge in Ca₃Ga₂Ge₄O₁₄ and the photoelectron spectrum of the valence electrons of Ca₃Ga₂Ge₄O₁₄ are in good agreement. The OKα-band changes its fine structure only slightly upon doping Ca₃Ga₂Ge₄O₁₄ with Ce or Eu. The investigations of intrinsic luminescence under X-rays excitation of Ca₃Ga₂Ge₄O₁₄ gallogermanate are presented. [ABSTRACT FROM AUTHOR]