(e ,e +ion ) study on electron-induced dissociative ionization of O2
Abstract
Electron-induced dissociative ionization of O2 has been investigated by means of (e ,e +ion ) spectroscopy. The linear momenta of the fragment ions have been measured in coincidence with electron energy-loss spectra for O2 at scattering angles of 2 .2∘ , 4 .2∘ , and 8 .2∘ using an incident energy of 1.4 keV. From the analysis of the data, partial ion yield spectra have been obtained for the B 2Σ , {c 4Σ+2 2Σ+2 4Σ} , {2 2Σ+2 4Σ} , and 3 2Σ ionization, allowing us to assess state-specific momentum-transfer dependence of the relative ionization cross sections. It has been shown that the shape resonance in the B 2Σ channel is substantially suppressed by the contributions of electric nondipole transitions. To get insight into the stereodynamics in the electron-O2 collision processes, the angular distributions of the fragment ions have been examined. It has been revealed that the (e ,e +ion ) cross section for the 2 σg→1 πg autoionization band exhibits a characteristic angular distribution reflecting the anisotropic shape of the molecular orbital to which the target electron is excited.
- Publication:
-
Physical Review A
- Pub Date:
- February 2019
- DOI:
- 10.1103/PhysRevA.99.022704
- Bibcode:
- 2019PhRvA..99b2704W