Theoretical Investigation of the Diatomic Dication C 02 +

Ab initio calculations of electronic states of the dication C02+, using highly efficient configuration-interattion procedures, are reported. For the lower states, energies are believed to be accurate to within 0.2 eV, but the higher states are less reliable. The complexity of the problem is due to mixing of states of radically different character, such as strongly bound chargepolarization states correlating with C2+ plus 0, and essentially Coulombic repulsion curves. For this reason it was not possible to obtain reliable results for internuclear separations greater than about 3 A. Energies and rotational predissociation lifetimes, of all (v,J) levels of the quasi-bound and bound states, have been calculated. The theoretical results have been compared with experimental information including the appearance energy of C02+, values of kinetic energy release associated with predissociation on the microsecond time scale, and Auger spectra.