CORE-VALENCE DOUBLY IONIZED STATES - GENERAL-ASPECTS, EXAMPLES, PRODUCTION MECHANISMS

Electronic double vacancies with one vacancy in the valence shell and one in the core play a role in several physical processes. Such core-v alence double vacancies are theoretically analyzed and related to poss ible experiments. The corresponding wavefunctions and energies for CO, N-2, and H2CO are computed using propagator and configuration interac tion methods. The numerical results are analyzed in some detail and ar e compared to the corresponding single valence vacancies. The analysis is performed by breaking up the binding energy of the double vacancy into the most relevant components, such as hale-hole repulsion and rel axation contributions. It is shown that the double ionization potentia l is essentially given by single ionization quantities. In particular, we find a kind of ''Koopmans theorem'' for those dicationic states wi th an outer valence hole: the double ionization potential (shifted by the core ionization energy) is approximately given by the valence orbi tal energy of the core ionized state. As typical for double vacancies we encounter, in addition, an interesting singlet-triplet separation p roblem. Intensities for the production of the dicationic states by val ence ionization out of a core ionized initial state are derived. The e xtent of valence hole localization in the dicationic states is analyze d by a two-hole population analysis. The analysis can be used to simul ate the production of core-valence vacancies via Auger decay. (C) 1996 American Institute of Physics.