THE STABILITY OF N-2(A-'5-SIGMA+G)

The energy and stability of the "high spin" 7Σ and 5Σ states of N2 have been the subject of many theoretical efforts. These states play an important role in N-atom recombination. The collisional coupling of these states to other excited electronic states strongly influences the electronic emission spectrum of N 2 observed in atom recombination. Since these states are not dipole coupled to lower excited electronic states of N2, they are considered metastable and are possible candidates for high energy density storage media. We have examined the stability of N2(5Σ) state in a discharge flow reactor. The 5Σ state is produced from the N2(A 3Σ) energy pooling reaction and probed via laser-induced fluorescence on the C″ 5Π′-A 5 transition. While no laser-induced fluorescence from excitation of the A′ state is observed, comparison of signal levels with laser-induced fluorescence on theB 3Πg-A 3Σ u- transition enables us to establish an upper limit on the gas phase lifetime of this state at pressures of a few Torr. Experimental evidence is presented which suggests that the primary mode of A′-state quenching is through collisional coupling to the B 3Πg state. However, other matrix isolation experiments suggest that the A′ state may be stabilized in cryogenic rare gas matrices. © 1990 American Institute of Physics.