A two-step process using internal conversion and fluorescence to stabilize the $6P_{\frac{3}{2}}11d$ autoionizing state of barium has been observed. The internal conversion produces very highly excited autoionizing Rydberg states, which then emit fluorescence to produce singly excited, bound states. Inclusion of this process should bring calculations closer to agreement with recent measurements of dielectronic recombination.

• Received 24 July 1986

DOI:https://doi.org/10.1103/PhysRevA.34.4508