Simultaneous measurements of the vibrational populations of CO₂ and N₂ in a nanosecond pulsed discharge

To study the vibrational kinetics of CO₂/N₂ mixtures, a ns-pulsed DC discharge is utilized to separate different energy transfer processes such as the e-V and V-V transfer in time. Previously, the vibrational populations of CO₂ in CO₂/N₂ mixtures were measured using quantum-cascade laser absorption spectroscopy [1]. To complement this work, a dual pump folded BOXCARS setup is used to measure the vibrational populations of N₂ and CO₂ simultaneously. A dynamic range of the spectra of approximately 4 orders of magnitude was achieved allowing for the measurement of N₂(v) states up to N₂(v=3) and in parallel the first excited state of the bending mode and asymmetric stretch mode of CO₂, respectively. The latter allows for a comparison with the previous QCLAS measurements. The combined set of vibrational populations and electric fields measured in our previous work [1] are compared with state-of-the-art kinetic simulations using the Lisbon Kinetics (LoKI) simulation tools [2].

[1] Christian A Busch et al 2025 J. Phys. D: Appl. Phys. 58 065202

[2] A. Tejero-del-Caz et al 2019 Plasma Sources Sci. Technol. 28 043001