The valence band of some light rare-earth metals studied by photoemission spectroscopy

The valence bands of La, Ce, Pr, and Nd have been studied by ultraviolet photoelectron spectroscopy (UPS) (He II, hv=40.8 eV) and compared to results from X-ray photoelectron spectroscopy (XPS)(Mg Kα_{1, 2}). The energy positions of the $\text{4?}$ levels are in good agreement with earlier XPS results and calculations based on estimates from optical and thermodynamic data. The widths of the sd bands and the $\text{4?}$ levels and the relative emission intensities are discussed.