  Anderson impurity model for semiconductor quantum dot is extended to take
into account both particle and hole branches of charge excitations. It is shown
that in dots with even number of electrons where the Kondo effect is absent in
the ground state, novel midgap excitonic states emerge in the energy spectrum
due to Kondo-type shake-up processes. The relevance of the model to rare earth
ions adsorbed on metallic surfaces is discussed.
