Showing papers by "Michael A. Dillon published in 1981"
TL;DR: In this article, the radial dipole matrix element with respect to the final-state wave function normalized in an energy-independent way near the origin is represented as a compact expression involving a polynomial of several degrees in a suitable variable.
Abstract: It is possible to represent an essential factor of the dipole oscillator‐strength distribution for a single‐electron continuum in terms of a compact expression involving a polynomial of several degrees in a suitable variable. The factor, which may be called the reduced oscillator‐strength distribution, is defined in terms of the radial dipole matrix element with respect to the final‐state wave function normalized in an energy‐independent way near the origin. The key variable is g = e/(e+I), where e is the kinetic energy of the ejected electron and I is the ionization threshold energy. The structure of the analytic representation has been identified through a study of the analytic properties of the dipole matrix element as a function of e. For illustration, H, He, Li, and Na atoms are treated explicitly. Implications of our results to molecules and multichannel cases are also indicated. The present findings will be especially useful for interpolation and extrapolation of experimental data.
15 citations
TL;DR: In this paper, the angular dependence of inelastically scattered electrons in O2 in the energy loss range 16 to 26 eV for incident electron energies between 75 and 400 eV, and for scattering angles between 2° and 12°.
Abstract: We have measured the angular dependence of inelastically scattered electrons in O2 in the energy‐loss range 16 to 26 eV for incident electron energies between 75 and 400 eV, and for scattering angles between 2° and 12°. For high incident energy and low scattering angle our energy loss spectra correspond to the known optical absorption spectrum. At higher scattering angles, four new structures appear in our spectra at 21.85, 23.30, 23.80, and 24.06 eV. These four structures are the lowest members of the first optically forbidden Rydberg series observed to converge to the O+2 c 4Σ−u limit at 24.56 eV. The calculated quantum defects for these levels are about 0.75. This value, combined with angular scattering propensity rules, indicates that the new Rydberg states occur by promotion of an electron from the σu2s orbital to npσu orbitals, where n = 3,4,5,6. A consideration of the propensity rules for excitation of forbidden transitions by high energy electron impact suggest the term symbol of the new Rydberg s...
14 citations
TL;DR: In this article, the energy loss spectra for e−Ar and e−Ne collisions was measured using the Born approximation, and it was demonstrated that information on quasi−discrete autoionizing states can be obtained via the Born approximations.
Abstract: Using 200 eV incident electrons, the energy‐loss spectra is measured for e‐Ar and e‐Ne collisions. It is demonstrated that information on quasi‐discrete autoionizing states can be obtained via the Born approximation.(AIP)
4 citations