1137. ジルコニウム水素化物および水素固溶体の電子構造

抄録

Electronic structures of zirconium hydride and hydrogen solid solution have been evaluated by the X-ray photoelectron spectroscopy and first-principles molecular orbital calculation. From the valence band spectra of the solid zirconium hydride, the occurrence of the valence electron transfer from Zr 4d band to Zr-H bonding state was found to induce the reduction of Zr-Zr metallic bonds with increasing the hydrogen content, because of the formation of Zr-H covalence bonds. In the hydrogen solid solution, the 4d electrons were, as well as the hydrides, drawn off from the metallic bond onto the Zr-H bond, leaving less charge to participate in the Zr-Zr bonds. When hydrogen atoms reside in the zirconium metal, the electron transfer caused by the spatial distribution of H 1s electrons induces the charge depletion between the first-nearest zirconium atoms, which consequently weakens the surrounding metal-metal bonds. These results could elucidate qualitatively the datum of the elastic moduli of the solid zirconium hydride and the hydride solid solution obtained in our previous studies.