Predissociation and perturbations in the C2Σu+state of N2+from interaction with the B2Σu+state

The homogeneous predissociation C→B in N2 + is treated theoretically in the adiabatic representation, where the coupling is produced by the nuclear kinetic energy operator. The electronic matrix elements of the operators ϖ/ϖR and ϖ2/ϖR 2 are evaluated from results of ab initio CI calculations on the electronic structure. These elements are strongly dependent on internuclear distance and behave very nearly as expected for a zero-order avoided crossing in the B and C states. Experimental RKR potentials are used to generate the nuclear motion wavefunctions, which are then used together with the ab initio electronic elements to calculate the vibronic integrals. The calculated predissociative decay rates correctly reproduce the observed vibrational and isotopic dependence of the C-state predissociation. Similar calculations give the correct order of magnitude for an observed perturbation in v = 2 of the C state, which lies below the predissociation limit.