The effects of the pressure and discharge voltage on the spectral intensities of thesecond positive and first negative systems were studied in a pulsed nitrogen discharge supersonicfree-jet. The results show that a stabilized discharge condition was reached when the vacuumchamber pressure increased to 100 Pa. Both N_2(C^3∏_u) and N_2^+(B^2∑_u^+) states were highly populatedat a pressure of 100 Pa to 130 Pa. The active state N_2(C^3∏_u)could be selectively populatedat a low pressure of 10 Pa and a discharge voltage of 4500 V. Different populating mechanismsunder the experimental conditions for N_2(C^3∏_u) and N_2^+(B^2∑_u^+) states were proposed to accountfor the experimental results.
