Local bond-electron-energy relaxation of Mo atomic clusters and solid skins

Abstract

A combination of tight-binding theory, bond order–length–strength correlation and non-bonding-electron polarization notions, photoelectron spectrometrics, and density functional theory calculations has enabled us to examine the effect of atomic undercoordination on local bond-electron-energy relaxation pertaining to Mo(100, 110) skins and atomic clusters. This exercise has led to the following quantitative information: (i) the atomic Mo 3d_5/2 energy level located at 224.862 ± 0.004 eV shifts 2.707 eV deeper upon bulk formation; (ii) the skin local bond is subject to a 9.80% contraction; and (iii) 5.952e charge transfers from the inner to the outermost skin layer. Furthermore, the E_4s level shifts from 61.229 eV for Mo₅₉ to 61.620 eV for the Mo₁₅ cluster and the valence band undergoes a 1.057 eV upward shift. The globally positive core-level shift arises from local quantum entrapment due to bond contraction and strength gain. The densely entrapped core electrons polarize the valence electrons and hence raise the valence band energy.