Calculations of energies of intrashell doubly excited states of beryllium-like ions

Energy levels of doubly excited states of beryllium-like ions are calculated using the conventional configuration-interaction method. The interactions of the two outer electrons with the inert 1s 2 core electrons are represented by a model potential. The resulting energies of 1s 2 3l3l' and 1s 2 4l4l' doubly excited states, designated in terms of the K, T and A correlation quantum numbers, are used to identify the Auger electron spectra derived from the collision of multiply charged ions with atoms and molecules. The systematics of energy levels is analysed and compared with the supermultiplet structure of doubly excited states of helium-like ions.