Vibrational Excitation and Compound States in NO

Abstract

The cross section for elastic scattering by electron impact on NO shows resonances in the energy range 0-2 eV. These resonances, with a spacing of about 0.16 eV (${\omega }_e=0.17\mathrm{}$ eV), are associated with vibrational levels of ${\mathrm{NO}}^{-}$, and there is a near-coincidence in energy between the 4th vibrational state of NO and the 6th vibrational state of ${\mathrm{NO}}^{-}$. The width of these resonances increases monotonically from 0.02 to 0.10 eV as the vibrational quantum number of ${\mathrm{NO}}^{-}$ goes from 1 to 6. The energy dependence of the vibrational cross sections exhibits peaks at the positions of these resonances, and the magnitude of these peaks is measured. The vibrational states of ${\mathrm{NO}}^{-}$ can decay by the emission of an electron into various vibrational levels of NO. The branching ratio for a few of these decays is measured. A potential energy diagram of ${\mathrm{NO}}^{-}$ is drawn, using the experimental evidence.