Spectroscopic study of N2O+(A 2Σ+) by photofragment excitation spectrum

Photofragment NO+ excitation spectrum of N2O+ ions has been studied in the wavelength range of 278–328 nm, where the parent N2O+ ions were state-selectively prepared at the X 2Π1/2,3/2(000) levels by [3+1] multi-photon ionization of jet-cooled N2O molecules at 360.55 nm. The spectrum was attributed completely to the A 2Σ+←X 2Π3/2,1/2(000) electronic transition of N2O+. Totally 47 vibronic bands associated to 24 vibrational levels of the A 2Σ+ state were identified in the present work, most of which were observed for the first time. The sufficient spectroscopic data made it possible to investigate the Fermi-resonance between the ν1 and ν2 vibrational modes at the A 2Σ+ state. Based on the assignment, the spectral constants of the A 2Σ+ state, such as vibrational frequencies, anharmonic constants, and Fermi interaction constant, were determined with relatively high reliability and precision.