Double photoexcitation of 2p and 4f electrons in curium

The L3-edge X-ray absorption spectrum of the aqua trivalent Cm ion in aqueous solution exhibits a double photoexcitation involving 2p and 4f electrons. The resonance structure of the multielectron excitation reveals a shake-up process at 508.1 ± 10 eV. The data indicate a monotonic increase of the [2p4f] excitation energy between elements of sixth period (Au, Hg, Pb and Bi) and the early actinides (Th, Pa, U, Np, Pu, Am and Cm).