4D(-1) MULTIPLET STRUCTURE OF RARE-EARTH ATOMS STUDIED BY PHOTOELECTRON-ION COINCIDENCE SPECTROSCOPY

The 4d photoelectron spectra of atomic lanthanides Ce, Pr, Nd, Sm, and Eu have been measured using synchrotron radiation. The multiplet stru cture of the 4d(-1) hole states has been investigated by applying the electron-ion coincidence technique in the form of final ion-charge res olving electron (FIRE) spectroscopy. FIRE spectroscopy is a spin-sensi tive method for the study of 4d(-1) decay processes. Photoelectron spe ctra have been calculated in the one-configuration approximation for t he rare-earth atoms from Ce to Gd and FIRE spectra have been calculate d for Ce, Pr. Nd, Sm, and Eu. Comparing theoretical and experimental r esults, we discuss the trend of the development of the 4d(-1) multiple t structure from Ce to Gd.