ELECTRONIC EXCITATION OF ATMOSPHERIC MOLECULES BY PROTON IMPACT

Electronic and vibrational excitation of N2, O2, CO and NO by 3 keV protons has been investigated by means of high resolution translational energy spectroscopy. The dominant transitions (X1-SIGMA-g+ --> a1-PI-g) in N2 and (X1-SIGMA+ --> A1-PI) in CO are well resolved and the relative intensities for the vibrational excitations have been determined. The dominant structures in O2 result from excitation to the B3-SIGMA-u- and A3-SIGMA-u+ states which leads to dissociation of the O2 molecule. The most prominent feature in NO is difficult to identify because of the existence of eleven doublet electronic states from the B'2-DELTA-i (7.48 eV) to the S2-SIGMA+ (8.29 eV) state. Three well-defined peaks observed at 5.5 eV to 6.1 eV have been assigned to the transitions X2-PI-r (upsilon = 0) --> A2-SIGMA+ (upsilon = 0, 1, 2) of NO.