Collision-induced emission spectra from 190-1020 nm were obtained for N-2(+center dot)/Ar collisions at laboratory frame collision energies from 2 to 8 keV. The relative emission intensities of N-2(+center dot), N+, and N-center dot are independent of the ion translational energy within the Studied energy range, supporting the curve-crossing mechanism for collisional excitation. The role of the target gas in keV N-2(+center dot)/He and N-2(+center dot)/Ar collisions was investigated by both emission spectroscopy and theoretical calculations. Adiabatic potential energy surfaces calculated at the CISD/6-311+G(2df) level of theory for N-2(+center dot)/He and N-2(+center dot)/Ar collisions indicate that excitation to the A (2)Pi(u) and B (2)Sigma(+)(u) states involves curve-crossing first to the C-2 Sigma(+)(u) state, and the difference in N-2(+center dot) emission intensities from the two systems can be accounted for by the slope difference at the crossing points based on the Landau-Zener curve-crossing model.