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Abstract: The 2p3/2 core-level binding energy (BE) shifts of Fe surface and Fe nanoparticles have been analyzed by considering the bond order-length-strength (BOLS) correlation mechanism in decomposition of the X-ray photoelectron spectrum (XPS). It turns out that the Fe 2p3/2 BE shifts positively by 2.17eV from the atomic value of 704.52eV to the bulk value of 706.69eV and that a further 0.32 and 0.16eV positive shift occurs, respectively, to the top and the second atomic layers. Consistency between BOLS predictions and the measured size dependence of BE shift clarifies the dominance of the broken-bond-induced local strain and quantum trapping in perturbing the Hamiltonian and hence the positive shift of the 2p3/2 BE of Fe surface and Fe nanostructures. [Copyright &y& Elsevier]

We examined the combined effect of atomic under- and hetero-coordination on the bond relaxation and electronic binding energy of Sc, Zr, and ScZr alloying using a combination of the bond-order–length–strength (BOLS) correlation and density functional theory (DFT) calculations. Observations strongly emphasize the relevance of core-level shifts as reliable X-ray photoelectron spectroscopy experimental descriptors of core–shell catalysis reactivity, along with under-coordinated atoms in bimetallic transition metal systems. The BOLS–DFT method provides enhanced catalysis reactivity and detects surface and alloy configurations, opening up the possibility to investigate more complex systems with irregularly under- and hetero-coordinated atoms. [ABSTRACT FROM AUTHOR]