Double photoexcitation [2(s,p)4(p,d)] in the Xe-isoelectronic series Cs+, Ba2+, La3+

Using the standard ansatz, the single, strongly dissipated harmonic component of EXAFS in aqueous medium is eliminated from L-shell absorption spectra of Xe-like ions Cs+, Ba2+, La3+. The remaining structures in the spectra are interpreted as double photoexcitations into [2(s,p)4(p,d)] vacancy states : they are analogous to the corresponding structures in absorption spectra of xenon, their energies agree fully with MCDF energies. Their relative probabilities are found to increase along the isoelectronic series, proportionally to the intensity of the "white line" 2p→5d. For the first time, an "adiabatic" change of double excitation features is studied