Product branching in predissociation of the e 1Πu, e′ 1Σ+u, and b′ 1Σ+u states of N2

A measurement of the N(2D0) and N(2P0) yields in predissociation of the e 1Πu, e′ 1Σ+u, and b′ 1Σ+u states of molecular nitrogen is reported using photofragment spectroscopy. These states are prepared by laser excitation from the long-lived a″ 1Σ+g (v=0) level in a fast molecular beam. A position- and time-sensitive detector is used to monitor the two correlated fragments produced by single molecular dissociation events. The translational energy imparted in the fragments establishes the electronic energy of the resulting nitrogen atoms and hence the branching among the available dissociation limits of nitrogen. Extremely pronounced rotational dependence in the branching yields is observed for the e and e′ members. The dependence mimics, in part, known molecular perturbation of the Rydberg states, and it reveals a complex competition among continuum states for the population in the Rydbergs.