Photoabsorption and photoion spectroscopy of atomic uranium in the region of 6p and 5d excitations - art. no. 062706

The photoabsorption process in atomic uranium has been investigated experim entally and theoretically in the 15-150-eV region. Using the dual laser pla sma technique, the 6p photoabsorption spectrum has been recorded while for the first time the 5d region has been remeasured photoelectrically using bo th photoabsorption and photoion spectroscopy. Interpretation of the photoab sorption spectra is supported by Hartree-Fock calculations which take into account spin-flip decay and the interaction of many discrete states with ma ny continua. The 6p spectrum is entirely dominated by spin-orbit split 6p-- >6d transitions. The Sd-subshell photoabsorption is shown to consist predom inantly of discrete 5d-->5f excitations; here the electrostatic and spin-or bit interactions are comparable in strength.