Optical radiation from nitrogen and air at high pressure excited by energetic electrons

Abstract

The spectral characteristics and fluorescent efficiencies for electron excitation of nitrogen and air at 600 Torr have been determined. Results are presented for the efficiency of conversion of electron energy to optical radiation in approximately one hundred resolved spectral components of air and nitrogen between 3200 and 10 800 Å when bombarded by 50-keV electrons. The total fluorescent efficiency under these conditions is (0.14±0.02)% for nitrogen and (6.7±1.0)×10-3% for air. In nitrogen the first positive (B 3IIg→A 3∑ u+), second positive (C 3IIu→B 3IIg), Gaydon green, Herman infrared, and Goldstein-Kaplan (C′ 3IIu→B 3IIg) band systems of N2 and the first negative (B 2∑ u+→X 2∑g+) band system of N2+ were observed. The (0-2) and (0-3) transitions of the Herman infrared system and [N I]32 ( 2D-2P) forbidden doublet at 1.04 μ, previously unreported in the laboratory, were observed. In air the first positive and second positive band systems of N2 and the first negative band system of N2+ were observed as well as atomic spectra of nitrogen, oxygen, and argon.