Emission spectra in the 2850-to 4300-3, region produced by 0.7-to 10-keV impact of H +, H ø, and He + on CO: and N:O have been observed. The emission consists almost exclusively of the A-X and B-X systems of CO: + and the A-X system of N:O +. There are no emissions from excited fragments of the parent molecules. Cross sections for proton impact excitation reach maxima of 1-4 X 10-x6 cm: in the collision energy range observed. Cross sections for H ø excitation reach maxima of 0.4-1 X l0 -x6 cm :. This paper reports an analysis of the source and intensity of near-ultraviolet radiation which results from collisions of H +, H ø, and He + with the isoelectronic molecules COo. and No.O. This study considers collision energies between 0.7 and l0 keV and complements work which has been done at both higher [Haugh and Birely, 1974; Birely and Johnson, 1975] and lower energies [Coplan and Mentall, 1973]. The intermediate energy region considered here is important because the cross-section maxima for the production of the major emission features arising from these collisions occur in this range. In addition, the present collision experiments simulate some of the optical excitation processes which occur in the interaction of the solar wind with the atmospheres of Mars and Venus as well as any proton auroral phenomena which occur on these planets. EXPERIMENT As shown schematically in Figure 1, the apparatus consists of a particle beam source, a collision chamber, and an optical detection system. Ions are produced in a duoplasmatron ion source. Ions from this source enter a low-resolution Wien filter, which serves as a mass filter. Ions transmitted by the mass filter are deflected 90 ø by an electrostatic 'beam bender.' This bend in the beam path ensures that light from the ion source does not interfere with optical measurements downstream. To produce a neutral beam, some of the ions in the beam may be neutralized in charge exchange collisions with Ar atoms contained in a neutralization chamber, which precedes the collision chamber. An electrostatic broom located between the two chambers removes unwanted ions when a beam of neutrals is desired. paratus. Thanks are also due to John H. Bitely for discussions regarding this work and for preprints of his papers and to D. L. Judge and L. C. Lee for preprints of their work on N,O +.
