Electron-ion recombination measurements in CO at high pressures

The electron-ion recombination rate has been measured in a high-pressure CO discharge at room temperature and at pressures from 100 to 700 Torr. The effective two-body rate coefficient was found to be in the range 10−7−10−6 cm3/sec, with an electron temperature dependence of Te−1.6 associated with the average electron energy from 0.2 to 0.7 eV. The results indicate a small pressure dependence, of less than a factor of 2, over the experimental pressure range. The principal ion at these pressures was probably the dimer, C2O2+, or a high-order polymer ion based on ion-molecule reactions in CO reported in the literature.