1s shake-up excitations in Ge and GeO2 by high-energy x-ray photoemission spectroscopy

X-ray photoemission spectra of Ge and GeO2 have been collected using high-energy photons (E-gamma = 13.6 keV and E-gamma=11.85 keV). The experiment was carried out using a high brilliance undulator source of the European Synchrotron Radiation Facility. The comparison between photoemission spectra at different energies and electron-energy-loss spectra allowed us to unambiguously identify shake-up satellites of the Is photoelectron peak involving additional excitations of 3p and 3s electrons. These features are clearly visible in GeO2 at the energies of 152 eV and 208 eV above the 1s peak.