Materials at heterojunction interfaces demonstrate many physical and chemical properties that are indeed fascinating with mechanisms that need yet to be explored. We show herewith that the "interface charge and energy quantum entrapment due to bond order distortion and bond nature alteration" perturbs essentially the Hamiltonian and hence the binding energy of the CuPd alloy interface. Analyzing the X-ray photoelectron emission of the thermally induced evolution of the Cu 2p and Pd 3d core-level energies at the Cu-Pd interface before and after thermally alloying revealed that the Pd 3d and Cu 2p interfacial potential traps are 0.36 and 0.95 times deeper than the potential wells of the corresponding bulk constituents standing alone. (C) 2010 Elsevier B. V. All rights reserved.