Angular Dependence of Electron Impact Excitation Cross Sections of O2

摘要

The electronhyphen;impact excitation spectrum of O2has been studied at 20 and 45 eV impact energies and at scattering angles ranging from 10deg; to 90deg;. The angular behavior of the differential scattering cross sections for excitation of thea1Dgr;g,thinsp;b1Sgr;gplus;,thinsp;B3Sgr;uminus;states, for the 9.97 eV (``longest'' band), and the 10.29 eV (``second'' band) transitions, for the broad feature at 6.1 eV energyhyphen;loss (previously assigned to the excitation of theA3Sgr;uplus;state), and for elastic scattering has been determined. The experimentally measured relative differential and integral cross sections for these processes have been approximately normalized to the absolute scale. The intensities of the different transitions in optical and electronhyphen;impact spectra are compared and the importance of spinhyphen;orbit coupling and exchange processes are discussed. It is found that the energyhyphen;loss feature at 6.1 eV in the electronhyphen;impact spectrum is mostly due to the excitation of thec1Sgr;uminus;state. This new assignment is supported by the angular and energy dependence of the scattering cross section (and by the intensity pattern found in various electron impact processes).