Radiative electron capture by high-energy oxygen ions in hydrogen and helium

X rays produced in the collisions of 94--222-MeV O{sup 8+} ions with H{sub 2} and He targets have been measured. Resulting spectra have been analyzed to determine absolute yields, profile widths, and energies for x rays emitted in the process of radiative electron capture (REC). These measurements are compared with predictions based on impulse-approximation calculations, using differential cross sections for radiative recombination (RR) folded with target Compton profiles. Measured absolute peak energy positions and profiles are found to be in good agreement with these simple theoretical estimates. Cross sections derived from REC yields are compared with other measurements and with theoretical RR values. A small systematic discrepancy between experimental and theoretical cross sections is noted.