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 I 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.