Double-electron excitations in L-edges X-ray-absorption spectra of W, ir and cs oxide compounds

Very strong double-electron excitations have been observed for the first time in the W, Ir L₃-edge and Cs L_{1, 2, 3}-edges X-ray-absorption spectra of tungsten and iridium oxide thin films and cesium oxide containing glasses. They are expressed as peaks with a width of several electron-volts located at the absorption background above the edge. The positions of these features are in good agreement with atomic calculations in the Z+l approximation. They can be attributed to the transitions 2p4d→ 5d5d for the L2, 3 -edges and 2s4d→ 6p5d for the L₁-edge with the dipole selection rules for the angular and total angular momentum ∆L = ±1, ∆J = 0, ±1.