Photoelectron spectra excited by x radiation are reported for the band-structure part on clean films of the rare-earth metals Nd, Sm, Dy, and Er. The dominant part of the spectra is due to excitation of $4f$ electrons. The spectra exhibit a complex and extended structure which is interpreted in terms of multiplet splitting of the final state in the photoemission process.

• Received 16 November 1970

DOI:https://doi.org/10.1103/PhysRevLett.26.432