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

Threshold photoelectron spectra of N2+ 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 C2Sigmau+ state. The second progression was identified as the transition to the second state of 2Pig 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 2Sigmau- 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 2Deltau and 2(2) Piu states by similar comparison with previous theories. Copyright 1997 Academic Press. Copyright 1997Academic Press