Studies of the O2 3Πg(V) valence states and 3Πg(R) Rydberg state in the Schumann–Runge continuum from ejected and scattered electron spectra

Publisher Website
Google Scholar
Abstract
Electron-impact energy-loss spectra are obtained in O2 in the energy-loss range of 7 to 10 eV. These spectra contain some discrete features resulting from scattered electrons following excitation of Rydberg states, and other features from ejected electrons following decay of O2−Feshbach resonances into valence electronic states in the continuum via the reaction e+O2 (X 3Sg−)→(O2−)→O2 3Rg(V) +eejected. From the known O2− energies and from measurements of the ejected electron energies, we find the 3Rg(V) state to extend over an energy range of only about 0.20 eV in the Franck–Condon region of the ground state, contrary to some previous experimental and theoretical results. From measurements of scattered electrons, effective excitation functions of several vibrational levels of the 3Rg(R) Rydberg state are obtained. Of the many O2− Feshbach resonances known to exist in this energy regions, only one decays strongly into the 3Rg(R) state.