MOLECULAR-BEAM EXPERIMENTS CLARIFYING CONFLICTING REPORTS ON MAGNETIC-FIELD EFFECTS IN NO(B) AFTERGLOWS

A search for NO(B-X) beta-band emission from the impact of metastable Ar on N2O and metastable N-2 on NO was conducted under single-collisio n conditions. For the cross sections to produce NO(B), upper limits of 0.001 and 0.1 Angstrom(2), respectively, were established. The beta-b and emission reported from afterglow studies of these two reactions wa s therefore probably due to a secondary process. Most likely NO(B (2) Pi) was formed via NO(a (4) Pi) as a precursor. This would explain the reported magnetic-field induced quenching of the beta-band intensity, by the mechanism studied by us in a beam of NO(a (4) Pi). On the othe r hand, we detected beta-band emission from the interaction of a beam containing metastable N atoms (as well as molecules) with N2O. This ag rees with corresponding afterglow studies, where no magnetic field eff ect on this emission was observed. NO(B) being the primary product in this case, magnetic quenching would not be expected.