A b i n i t i o calculations of potential energy curves and transition moments of 1Σ+g and 1Σ+u states of N2

The valence, Rydberg, and ion pair characteristics of 1Σ+u states of N2 are studied in ab initio calculations involving selectively optimized basis sets of Slater-type functions and configuration mixing. Potential energy curves, as well as transition dipole moments and second moments of charge as a function of internuclear separation, are reported for 1Σ+g and 1Σ+u states. Transition dipole moments are in good agreement with experiment as are spectroscopic constants for the observed states. Analysis of the second moment and transition moment functions for the lowest 1Σ+u state shows clearly a transformation from atom pair to valence to ion pair to nearly pure Rydberg character as a function of internuclear separation between the separated atoms and the united atom limits.