Electron Transmission Spectroscopy: Core-Excited Resonances in Diatomic Molecules

Abstract

A high-resolution and high-sensitivity electron transmission spectrometer is used to study sharp structures in the total scattering cross section of ${\mathrm{H}}_2$, ${\mathrm{D}}_2$, ${\mathrm{O}}_2$, NO, ${\mathrm{N}}_2$, and CO. Many new resonances are found, some of which form bands which consist of progressions of negative-ion vibronic states. The existence of bands makes the identification of temporary negative-ion states easier, since the spacing and the magnitudes of the structure can be compared with the appropriate parameters of various positive-ion cores. The most prominent features observed consist of two Rydberg electrons attached to a particular positive-ion core.