PCI effects in (e,e' Auger) and (e,2e) cross sections: Ar 2p

Electron - Auger Electron Coincidence Experiments: Current Status and Future Prospects

“…Thus the coincidence experiments, because they enable one to select specific kinematic conditions, can have the effect of accentuating or removing PCI effects in the observed lineshapes. Further measurements of the effect of PCI on the Auger lineshape have been reported by Sandner and V6lkel (1984), Stefani et al (1986), Lohmann (1991 and Weigold (1992). Fig.…”

“…A number of theoretical models of PCI have been developed, including those of van der Straten et al (1988), Kuchiev andSheinerman (1989, 1994) and Armen et al (1987), and the lineshapes predicted by these models generally show good agreement with the experimental data. The confirmation of the presence of PCI in the final channel means that the Auger process may no longer be treated as a two-step process, in which the initial ionisation and the subsequent decay of the ion are treated as independent events.…”

Recent Applications of (e, 2e) Techniques

“…Finally we note that it is apparent from Table 3 that there are quite a few satellites observed in the PES spectra that are not identified in the current EMS measurements. These satellites are of 2p and 2D manifold symmetry and are very weak in intensity (see Svensson et al 1988). Consequently they are dominated, in the EMS experiment, by the 2S satellites in their vicinity and thus are not seen.…”

“…(2) The experimental development of atomic and molecular physics at an increasing number of synchrotron radiation centres makes feasible photoionisation studies of gases at low pressures with synchrotron radiation of variable photon energy (Svensson et al 1988). (3) The measured spectroscopic factors of satellites in EMS valence electron spectra are independent of the incident energy and the target electron momentum, but differ from the corresponding photoelectron spectroscopy (PES) values, which are energy dependent even at high momentum (McCarthy and Weigold 1991).…”

“…This has mainly focussed on post collision interaction effects (PCI) in the ionisation of inner shells resulting in the emission of Auger electrons, particularly the ionisation of the 2p shell of argon Crowe 1982, 1984;Sandner and Volkel 1984;Stefani et al 1986;Lohmann 1991;Lohmann et al 1992;Waterhouse et al 1993;Bell et al 1993;Kuchiev and Sheinerman 1994). The reaction has also been used to study the correlations between resonance and direct ionisation amplitudes in the autoionising region of helium e.g.…”