MULTIELECTRON INNER-SHELL PHOTOEXCITATION IN ABSORPTION-SPECTRA OF KR - THEORY AND EXPERIMENT

The probability of Kr 1s photoionization alone and accompanied by 4p, 3d, 3p, 2s, and 2s4p excitations has been calculated as a function of photon energy in the vicinity of the respective thresholds; pertinent energies have been computed including relativistic, quantum-electrodynamic, and relaxation effects. Sharp features from two-electron excitations are expected in absorption spectra only if at least one of the electrons undergoes a transition to a bound state; this becomes less probable in inner shells. An absorption-spectrometry experiment on Kr has been performed with synchrotron radiation; results generally confirm the predictions but also point toward refinements that are required in the theory and the need for improvements in techniques and synchrotron-radiation sources.