DIELECTRONIC RECOMBINATION OF THE BE-LIKE IONS - C-2+, N-3+, O-4+, AND F-5+

The first measurements of dielectronic recombination rate coefficients associated with the 2s2p excitation in the Be-like ions C2+, N3+, O4+, and F5+ are reported. We observed the amount of electron capture attending the passage of MeV/nucleon ion beams through a collinear, magnetically confined, space-charged-limited electron beam as a function of relative energy. The initial beams contained large numbers of ions for which the metastable states of the term 2s2p 3P were populated, and the fraction of ions in the metastable states to those in the ground-state configuration 2s2 were measured. The experimental rate coefficients are consistent in magnitude and shape with rates determined from distorted-wave calculations of the dielectronic recombination cross sections. The large fraction of metastable states in the initial ion beams had a pronounced effect on the shape and magnitude of the rate coefficients. © 1987 The American Physical Society.