The quadrupole ion mass spectrometer (QIMS) measured fluxes of barium and strontium ions during the CRRES G-1 chemical release in full Sun and the G-11b release in darkness. The barium ion fluxes detected in darkness were only a factor of 10 lower than the photoionization fluxes, indicating that the rate of nonsolar-UV ionization was at least a factor of 8 higher than literature values of charge transfer and collisional ionization cross sections would suggest. Model calculations of the QIMS ion fluxes using new, state-specific, calculations of the cross sections for ion-pair formation and charge transfer [Wolf and Hunton, this issue> demonstrate that the large nonphotoionization rates are consistent with significant metastable excitation in the neutral cloud but not with a ground state population. Upper limits to the collisional ionization rates for the conditions of the releases are 4.3¿10-3 s-1 for ion-pair production and 2.2¿10-3 s-1 for charge transfer. Collisions of high-energy electrons with the neutrals early in the cloud expansion is suggested as a mechanism for producing the metastable metal atoms. A similar analysis of the strontium data indicates that photoionization, charge transfer, and collisional ion-pair production alone cannot explain the large fluxes of strontium ions detected in the sunlit release. Associative ionization may therefore be an important ionization mechanism for that metal in sunlight. The implications of these results for analysis of space critical ionization velocity experiments are discussed. ¿ 1998 American Geophysical Union