Fast-ion beam laser spectroscopy of 14N2+ and 15N2+: high-resolution study of the (1, 2) band of the B2Σu+X2Σg+ system Original Research Article

We used laser-induced fluorescence combined with fast-ion beam laser spectroscopy to study at high resolution the rotational structure of the (1, 2) band of the first negative system (B2Σu+X2Σg+ of 14N2+ and 15N2+. Combining our laser-induced fluorescence data for the BX band and the new Fourier-transform emission data for the Meinel A-X system, we removed the correlation between the X and B state and we determined more accurate values of the molecular parameters for the excited and perturbed states of 14N2+ and 15N2+. The vibrational level v′ = 1 of the B state was found to be unperturbed within the observed rotational levels (4 < N < 20) for the isotope 15N2+ meanwhile the same level in 14N2+ appears perturbed by the level v = 11 of the A 2Πu state.