Quenching Rates of N$_2$(C$^3\Pi_u$ , $\nu$ = 0-4) States by O$_2$, N$_2$, H$_2$, CO$_2$ and CH$_4$

TL;DR

This study develops a protocol to measure collisional deexcitation rates of excited nitrogen states by various gases, providing new data for vibrational levels and improving understanding of nitrogen's collisional behavior.

Contribution

A novel experimental protocol for measuring N$_2$(C) state deexcitation rates by multiple gases, including new data for previously unmeasured vibrational levels.

Findings

Measured rate constants for N$_2$(C, ν=0-4) deexcitation.

Provided new values for missing vibrational levels.

Compared results with existing literature, confirming or updating previous data.

Abstract

This work presents the development of a protocol for the measurement of collisional deexcitation rate constants of N$_2$(C$^3\Pi_u$ , $\nu$ = 0-4) States by O$_2$, N$_2$, H$_2$, CO$_2$ and CH$_4$. Excited nitrogen is produced using nanosecond repetitively pulsed discharges. The applied voltage and the repetition frequencies are adjusted to minimize rotational and gas heating while keeping high electronic and vibrational excitation levels. The populations of the vibrational levels are measured using optical emission spectroscopy of the N$_2$(C $\to$ B,$\Delta_\nu=0$) vibrational bands. Rate coefficients for each vibrational level are then determined from the measured lifetimes. The results are compared to the available literature and new values are provided for the missing vibrational levels.