Exotic hole states of atoms created in the field of an X-ray free electron laser: Double K-vacancies in neon

Present article is dedicated to theoretical study of excitation and decay of a double K-vacancy during ionization of the Ne+(1s12s22p6) ion in the resonance Ne+(1s02s22p63p) region by the R-matrix method with B-splines. The resonance width in the photoabsorption cross section is crucially determined by Auger decay of the state Ne+(1s02s22p63p) with a spectator 3p electron. The Auger electron spectra from the decay of the double K-vacancy are obtained taking into account the photon beam width typical for such laser energies and the resolution of the electronic detector. The spectra correspond to the experiment with the detection of electrons for coincidences with the charge state of the ion. An experimental study of the process is available with modern X-ray free electron lasers.