PHOTODISSOCIATION OF O2 AND N2 IN FAR VACUUM UV AND PRODUCTION OF EXCITED O AND N ATOMS

Photodissociation of O2 and N2 yielding highly excited O and N atoms has been investigated in the region from 1000 to 450 Å by observing the fluorescence of fragments in the region between 1500 and 1100 Å. Fluorescence intensities were measured as a function of the incident wavelength. The following dissociation processes have been identified: O2→O(3s3S0)+O(3P), →O(3p3P)+O(3P), →O(3s1D 0)+O(3P), N2→N(3s4P)+N( 4S0), →N(3s2P)+N(2D 0). The threshold wavelengths of these processes coincide closely with the corresponding dissociation energies. The fluorescence intensities of the 1305- and 1200-Å resonance lines of O and N, respectively, were calibrated and absolute cross sections for the production of O(3s 3S0) and N(3s4P) have been determined. Depending on the incident wavelength, cross sections of up to 4×10 -18 and 5×10-19 cm2 are found for the 0(3s2S0) and N(3s4P) production, respectively.