Observation of electron impact inner-shell excitation of argon by means of satellite Auger spectra

Abstract

We have studied the inner-shell excited states of argon below the 2p thresholds for electron-impact excitation in the range of the incident energy E 0 = 275-1700 eV. We carried this out through the measurement of the electrons emitted during the decay of the states. The corresponding satellite peaks in the spectra of the emitted electrons were separated from the normal (diagram) LMM Auger peaks by a special evaluating process. We observed the satellite peaks coming from the 2p −1 (2 P 3/2)4s → 3p −2 (1 D)4s, 2p −1 (2 P 3/2)4p → 3p −2 (1 D)4p and 2p −1 (2 P 3/2)3d → 3p −2 (1 D)4d transitions at all applied incident energies. The intensity of the satellite peaks increased approaching the ionization threshold (E 0 = 275-300 eV). Nevertheless in the range E 0 = 1000-1700 eV we could identify more satellites due to the lower continuous background and the smaller post-collision interaction effects.

Resonant Auger decay of Ar2p3/2−14sand2pParipás1, Palásthy2, Štuhec3 et al. 2010Phys. Rev. A4000View full textAdd to dashboardCite

“…The weak lines previously found by noncoincidence measurements [9] are the dominant spectral features in the present spectra (denoted by arrows). The signal leading to [3p 2 3 P ]nl final states is expected to be found at about 1.6 eV above the [3p 2 1 D]nl states.…”

“…We note that by outer-shell ]4p. Arrows denote peaks observed previously by the noncoincidence experiment [9], and a tentative assignment is given (see text).…”

“…These resonant processes occur at about 245-eV energy loss and are observed at relatively large scattering angles. Thus, the corresponding (e,2e) cross sections are very low, as evidenced by the previous noncoincidence measurement estimating about 1% contribution of the resonant process relative to the L 3 -M 23 M 23 diagram Auger decay at similar electron-impact energy [9]. Moreover, the excitation of the [2p 3/2 ]4p(J ) group of states by photons is forbidden, and there are yet no corresponding resonant Auger spectra reported in the literature.…”

“…In the past, a few hints about the resonant component of the L-MM Auger process were obtained by noncoincidence experiments performed at several electron-impact energies above the Ar L threshold [9,10]. These measurements aimed to separate very weak resonant signals from the signal of the diagram Auger lines.…”

Design Considerations of Distorted Field Cylindrical Mirror Electron Energy Analyzers

“…The energy and angular distribution of electrons coming from electron-atom collisions were measured by distorted field cylindrical mirror electron spectrometers in the laboratory [3]. In the previous years the spectrometer system was supplemented by a coincidence equipment, in order to detect two of the electrons which are ejected simultaneously in a single collision event.…”