The production of Ominus;from CO2by dissociative attachment has been studied with electrons having energies in the range 0ndash;20 eV. In addition to the two already well established peaks in the 0ndash;10 eV range, a third peak has been substantiated, at 13 eV. At room temperature the 13 eV peak cross section is approximately6 times; 10minus;21thinsp;cm2,rising to approximately2 times; 10minus;20thinsp;cm2at 1000deg;K. Measured Ominus;ion kinetic energy distributions corresponding to the three processes peaking at 4.4, 8.2, and 13.0 eV are presented and their relevance to previous work is discussed. In all three processes only the high energy tails of the ion energy distributions are found to be sensitive to electron energy, with a decreasingly small fraction of the available energy appearing as kinetic energy of separation of the fragments. In this respect the results are similar to previous measurements of Ominus;production from N2O.
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