Excitation of Meinel and the first negative band system at the collision of electrons and protons with the nitrogen molecule

Abstract

The absolute cross sections for the $e\ensuremath{-}{\mathrm{N}}_{2}$ and $p\ensuremath{-}{\mathrm{N}}_{2}$ collisions for the first negative ${B}^{2}{\ensuremath{\Sigma}}_{u}^{+}--{X}^{2}{\ensuremath{\Sigma}}_{g}^{+}$ and Meinel ${A}^{2}{\ensuremath{\Pi}}_{u}--{X}^{2}{\ensuremath{\Sigma}}_{g}^{+}$ bands have been measured in the energy region of $400--1500$ eV for electrons and $0.4--10$ keV for protons, respectively. Measurements are performed in the visible spectral region of $400--800$ nm by an optical spectroscopy method. The ratio of the cross sections of the Meinel band system to the cross section of the first negative band system ($0,0$) does not depend on the incident electron energy. The populations of vibrational levels corresponding to ${A}^{2}{\ensuremath{\Pi}}_{u}$ states are consistent with the Franck-Condon principle. The ratios of the cross sections of ($4,1$) to ($3,0$) bands and ($5,2$) to ($3,0$) bands exhibit slight dependence on the proton energy. A theoretical estimation within the quasimolecular approximation provides a reasonable description of the total cross section for the first negative band.