Production and Decay of Atomic Inner-Shell Vacancy States

Our recent investigations on the accuracy of the existing 1s-vacancy fluorescence and Auger data base, which is crucial for the interpretation of spectra from X-ray photoionized plasmas and for supernova remnants under conditions of non-equilibrium ionization, is reviewed. In particular, effects such as non-hydrogenic scaling, correct initial state averaging, configuration interaction (CI), and spin-orbit mixing, which were not included in the earlier calculations but sometimes affect profoundly our computed fluorescence yields, is discussed. Furthermore, the production of 1s-vacancy states through photoabsorption is reviewed, with emphasis on orbital relaxation and spectator Auger broadening of the resonance edge. How our recent oxygen photoabsorption data contribute to elemental abundance studies of the interstellar medium will also be discussed.