Non-equilibrium characteristics of vibrational and rotational temperatures of N₂-B and C States puffed onto argon arc jet plume

Abstract

Band spectra of the first positive (1PS) and the second positive (2PS) systems of nitrogen molecule are analyzed with an optical emission spectroscopy (OES) measurement when N 2 gas is puffed onto the Ar plasma jet. It is found that T v ; T r ; 0.17 eV for the C state, while T v ; 0.28-0.35 eV, and T r ; 0. 038-0.050 eV for the B state, all of which are determined by fitting the theoretically calculated spectrum with those measured experimentally. Since the electron temperature in the observed area is about 0.4 eV, it is naturally considered that the N 2 C states are mainly produced by the resonant energy transfer from the Ar metastable to the N 2 ground state. It is also considered that similar values of T v and T r of the C state are the approximate value of the Ar gas temperature. Meanwhile, the vibrational distribution of the B state shows that the B state is populated not only by the radiative decay of the C state but also from other collisional processes, since the Franck-Condon principle cannot predict the vibrational population of the B state from the C state.