The 2p3/2 binding energy shift of Fe surface and Fe nanoparticles

Analysis of the XPS data from Fe surface and nanostructures turned out that the Fe 2p3/2 energy shifts positively by 2.17 eV from the atomic value of 704.52 eV to the bulk of 706.69 eV and that a further 0.32 and 0.16 eV shift occurs, respectively, to the top and the second atomic layers. Consistency between theory and experiments clarifies the dominance of the broken-bond-induced local strain and quantum trapping in perturbing the Hamiltonian and hence the observed Fe 2p3/2 energy shifts.