Electronic Ion Polarizability, Optical Basicity and Metal (or Nonmetal) Binding Energy of Simple Oxides.

A suitable relationship between free-ion polarizability and metal (or nonmetal) outermost binding energy has been searched on the basis of the similarity in physical nature between electron binding energy and ionization energy. It has been suggested that outermost core-level binding energy can be used for relative measuring the cation polarizability. In general, cation polarizability increases with decreasing metal (or nonmetal) binding energy. Highly polarizable cations possess low outermost binding energy. Simultaneously, a systematic periodic change of the polarizability against the binding energy has been observed in the isoelectronic series. A decreasing of metal (or nonmetal) binding energy in XPS spectra of simple oxides is accompanied with decreasing of O1s binding energy, that is related to increased basicity. This could be explained on the basis of enhanced interaction between outermost metal core level and O2p orbitals responsible to increased electron donor ability of oxide ion.