New N2+Electronic States in the Region of 23–28 eV

Abstract Threshold photoelectron spectra of N 2 + were measured between 23.4 and 27.6 eV with high resolution and high intensity by using the penetrating field technique and synchrotron radiation. Five vibrational progressions were observed. The first of these progressions was the C 2 Σ u + state. The second progression was identified as the transition to the second state of 2 Π g symmetry found by P. Baltzer, M. Larsson, L. Karlsson, B. Wannberg, and M. Carlsson (1992. Phys. Rev. A 46, 5545). The third progression, which was discovered by F. Merkt and P. M. Guyon (1993. J. Chem. Phys. 99, 3400), can be designated as the 2 Σ u − state by comparison with previous theoretical study (E. W. Thulstrup and A. Andersen, 1975. J. Phys. B 8, 965). The fourth and fifth progressions were designated as the 2 Δ u and 2 2 Π u states by similar comparison with previous theories.