N 2 + Meinel band quenching coefficients for vibrational levels 0 and 1

Abstract

Experimental rate coefficients for the quenching of vibrational levels 0 and 1 of the N2+A2Πu state by N2 are presented. The experiments were performed using near-infrared observations of the N2+ Meinel bands excited by electron impact at several pressures of the N2 target/quenching gas. The total removal rate coefficients were derived from a Stern–Volmer analysis of the Meinel band intensities as a function of N2 density and yielded rate coefficients of (2.5 ± 0.5 × 10−10) and (5.6 ± 0.6 × 10−10) cm3⋅molecule−1⋅s−1 for vibrational levels 0 and 1, respectively. It is shown that rate coefficients increase with increasing vibrational level and decreasing energy gap. Our results impact modeling studies of the disturbed atmosphere and ionosphere as the reduced quenching rate coefficients for the preferentially excited A-state vibrational levels <2 lower the quenching altitude in the atmosphere by one scale height, or about 6 km.