| Popis: |
An analysis of the possible excitations in the outer part of the electronic structure of YV${\mathrm{O}}_{4}$, based on the measurement of the characteristic electron-energy losses and x-ray photoelectron spectra is presented. The loss structures below 12 eV and above 22 eV are consistent with the molecular-orbital diagram of the oxyanion V${\mathrm{O}}_{4}^{3\ensuremath{-}}$ obtained within the cluster-model approach. Plasmonlike collective excitations are found at an energy some 5 eV below the "free-valence-electron" value. Deeper O $2s$ electrons appear to be excited by electrons preferentially not in single-loss events, but together with some molecular orbitals or plasmons. Deeper V $3p$ electrons are also excited, with losses that exceed by a few eV the binding energies of these electrons. Yttrium states are found in the photoelectron spectra, but their excitation by electrons, although possible in principle, is not supported by our data. |
