Size dependence of core and valence binding energies in Pd nanoparticles: Interplay of quantum confinement and coordination reduction

An analysis is given of the electronic structure of Pd nanoparticles synthesized by inert gas evaporation technique. A study of the effect of size on various core and valence electrons in Pd nanoparticles reveals a varied dependence of binding energy of electrons in different electronic levels. The shift in the Pd x-ray photoelectron spectroscopy 4d valence band centroid is more than the core level shift. The results of the present study provide a direct evidence of interplay of quantum confinement (a size effect) and coordination reduction (a surface effect).