The reaction (NO-)-N-3 + HA --> (HNO)-H-1 + A(-) requires a spin conversion for transformation of ground-state reactants to ground-state products. The proton-transfer efficiencies of (NO-)-N-3 with several acids (CF3CO2H, HCl, CH3CO2H, H2S, (CH3)(3)CSH, CH3NO2, CH3SH, CF3(CH3)CHOH, CFH2CH2OH, and CH3OH) in the gas phase have been measured using Fourier transform ion cyclotron resonance (FT-ICR) spectrometry. Proton-transfer efficiency was found to vary dramatically with both the structure and acidity of HA. This variation is attributed to different lifetimes of the collision complex.