【摘要】 本文描述了金属表面上所含d电子的特性。并用金属间隙电子模型(IEM)描述了金属体相中d轨道的空间位置。进一步发展的该模型可以用来修正过渡金属d轨道的表征。给出了若干主要晶面的各种d轨道的特征以及各种d轨道的占据情况。更多还原

【Abstract】 There are changes in both the conduction electron density (e) and the d-electron density for the surface layer of transition metals. The lower coordination number for surface atoms and the change in symmetry of e and positive ion cores (M+) result in both a narrowing of the d-band and a shifting of d-orbital energies for different d-orbitals.The Interstitial Electron Model (IEM) gives a qualitative description of all these changes; metal electronic configurations and the sequence of d-orbital energies are tabulated for the major crystal planes of the FCC, HCP and BCC metal lattices.A major difference among the transition metals is due to the localization of binding d-electrons for metals with less than 1/2-filled d-shells and the localization of anti-binding d-electrons for metals with more than 1/2-filled d-shells. There are differences shown by the IEM also for d-energy level splittings as compared to other formulations because the IEM also takes into account the greater electron density in tetrahehral interstitial regions than the octahedral ones. For several surfaces there is a further splitting due to the differing emergence of d-orbitals directed above the surface layer of different lattice planes. That these surface changes are highly significant for metal surface properties is shown by such phenomena as the surface layer contraction of the inter-layer spacing and surface atom reconstruction.The IEM predicts enhanced ferromagnetism for Fe, Co and Ni surface atoms as a result of the localization of itinerant d-electrons (di) for the surface layer. It also makes plausible the appearance of ferromagnetism for surface atoms of V. The changes at the metal surface proposed by the IEM explain very well the greater core level binding energy observed in XPS experiments for surface atoms than for bulk atoms for metals on the left side of the periodic table and the lower surface atom value for metals on the right. It is anticipated that this description of the metal surface will be helpful in interpretation of chemisorption and selectivity in catalytic reactions.更多还原