VACUUM-ULTRAVIOLET PHOTOIONIZATION OF THE 5D ELEMENTS IN THE REGION OF THE 5P AND 4F EXCITATION

The results of recent VUV photoionization experiments of the 5d elemen ts Ta, W, Re, Ir and Pt using atomic beam technique, excitation with m onochromatized synchrotron radiation and detection of singly and doubl y charged photoions are discussed. Special attention is given to the r esonances caused by discrete transitions of the 5p and 4f electrons in to the unfilled 5d subshells. As there is a crossover of the 5p and 4f levels along the series of the 5d elements the result is a complicate d structure of the corresponding interacting resonances. The photoion spectra are compared with theoretical calculations carried out within the relativistic time dependent local density and the relativistic Har tree-Fock approximation.