Electron-impact excitation of nitric oxide(A2Σ+–X2Π)

Abstract

We report absolute optical emission cross sections for 31 vibrational transitions of the A 2 Σ + (v')-X 2 ∏(v) system of nitric oxide for electron-impact energies from threshold to 740 eV using the optical method and a crossed-beam geometry. Our measurements include emission bands originating in the v'=0, 1, 2, 3 vibrational levels and terminating in the v levels from 0 up to 11. We find good agreement between our emission cross sections, our measurements of the emission intensities from an rf discharge, and the intensities predicted by the Franck-Condon principle. We also obtain apparent level cross sections for the v'=0, 1, 2, 3 vibrational levels of the A 2 Σ + state; despite the presence of a cascade, these level cross sections are proportional to the direct excitation rates predicted by the Franck-Condon principle. We determine the total apparent cross section for the A 2 Σ electronic state to reach its peak value of 40X 10 - 1 9 cm 2 at 30 eV.