For decades, experts in the molecular beam field have been actively engaged in the characterization technology. A corona discharge supersonic free-jet was used as a source of nitrogen activated species in this work, which with a dual appearance potential spectroscopy (APS) and time-of-flight (TOF) approach, provided useful information about the nature and characteristics of the terminal beam. This analysis determined its constituents in both qualitative and quantitative forms.

The results proved that molecular nitrogen metastable molecules (A ³Σ_u⁺, W³Δ _u, a'¹Σ_u^-) and atomic nitrogen species (⁴S⁰, ²D ⁰, ²P⁰) co-existed at 1.75m downstream the source of the modulated beam. A³Σ_u ⁺ were the most populated molecules which comprised 1.37% number fraction of the terminal beam and supplied 2.99 ± 0.04×10¹⁷ metastables per steradian second at 12mA of the negative corona-discharge. The terminal beam traveled as fast as 4.16Mach and exhibited a kinetic temperature of 7305 ± 10°K. With a complete characterization of the molecular beam parameters, this study illustrates the high potential of the dual APS-TOF measurements for the reliable use of the nitrogen long-lived metastables economically produced by a corona discharge free jet.

Also, a detailed description of the molecular orbital energy-level diagrams and electron configurations of the molecular and atomic terms, are presented in order to better support the understanding of the metastable-excited-states behavior as well as their corresponding ionization channels and transitions.