(3)Pi Levels and Predissociations of N(2) near the 12.135-eV Dissociation Limit

The two predissociations in the second positive bands, C(3)Pi(u)-> B(3)Pi(g), have been re-examined in the light of recent spectroscopic studies of the N(2) spectrum. It is concluded that the predissociation of Buttenbender and Herzberg is due to a (5)Pi(u) state and not to a (3)Pi(u) state as formerly believed. However, a few details of the predissociation are not yet clearly explained. The second, less well-known predissociation. of Hori and Endo is interpreted as being in all probability due to the C' (3)Pi(u) state (the upper state of the Goldstein-Kaplan bands). This explanation requires that the C' state have a maximum in its potential curve at an internuclear distance of about 2.0 angstrom. The behavior of the C and C' potential curves, which should apparently intersect at about 1.4 angstrom, is interpreted as a noncrossing rule interaction. The vibrational structure in the region of the interaction is discussed and in particular the level reported by Pannetier et al. and that reported by Tanaka and Jursa are attributed to a mixture of nu = 5 of C and nu = 1 of C'. The level formerly tentatively assigned to nu = 1 of C' is now considered to be primarily nu = 2 of the same state. Some low-temperature afterglow mechanisms are discussed in terms of the new interpretations of the C and C' states. The (5)Pi(u) and (3)Pi(u) states which are to be expected in the energy range of interest are discussed theoretically by the application of both the molecular orbital and the Heitler-London methods and the conclusions are found to be consistent with the present interpretation of the experimental results.