R. Vercaemst et al., A DETAILED XPS STUDY OF THE RARE-EARTH COMPOUNDS EUS AND EUF3, Journal of electron spectroscopy and related phenomena, 74(1), 1995, pp. 45-56
Eus and EuF3 powder samples have been the subject of an extensive XPS
study. For both compounds, the valence state of Eu was examined, toget
her with its stability, with respect to X-ray dose, total exposure tim
e under XPS ambient (UHV) and XPS sputter time. Maximum likelihood com
mon factor analysis (MLCFA) has been applied in combination with XPS s
putter profiling to determine the correct number of chemical states pr
esent in the sample. In this context, the mixed-valence behaviour of E
u in these compounds is discussed. Furthermore, an explanation for the
XPS final state effects in the Eu3d, Eu4d and Eu4f photoionisation pr
ocess is proposed.