Triple differential cross section of single Ar(2p) ionization by electron impact in the keV region

The ionization of Mg 3s and 2p and He 1s has been studied in (e, 2e) experiments at about 1000 eV incident energy and 20 eV ejected electron energy for a momentum transfer between 0.5 and 2.1 au. The comparison with the predictions of the distorted wave Born approximation model shows a generally good agreement between experiment and theory. The differences observed between the He and Mg angular distributions can be explained as an initial state effect and are attributed to the differences between the He 1s and Mg 3s wavefunctions in the momentum space.

Section: Discussionsupporting

confidence: 91%

The ionization of Mg by electron impact at 1000 eV studied by (e, 2e) experiments

Bolognesi¹,

Bohachov²,

Borovik³

et al. 2007

“…The full curve in figure 3(b) is a distorted-wave Born approximation calculation, and indicates the level of agreement which has been achieved for atomic targets. Results on inner-shell ionization of argon (Bickert et al 1991, Cavanagh and Lohmann 1997, Taouil et al 1999, krypton (Cavanagh and Lohmann 1998) and xenon (Avaldi et al 1993) have shown that when the ejected electron energy is less than the binding energy of the orbital being ionized, a very large recoil peak, equal to or greater in intensity than the binary peak, is observed. The results of Avaldi et al (1990) on C(1s) ionization in C 2 H 2 exhibit very similar behaviour.…”

Section: Resultsmentioning

confidence: 99%

“…The coplanar asymmetric measurements of Avaldi et al (1990) on C 1s ionization in C 2 H 2 also showed a shift of the (unexpectedly large) recoil peak to smaller angles, similar to that observed in N 2 . Doering and Yang suggest that such a shift is thus characteristic of molecular ionization as opposed to atomic ionization; however, recent studies of atomic inner-shell ionization (Bickert et al 1991, Zhang et al 1992, Cavanagh and Lohmann 1997, 1998, Taouil et al 1999 have revealed that the presence of a very large recoil peak and its shift to smaller angles is also associated with inner-shell ionization. These results suggest that valence-shell molecular ionization has more in common with innershell than valence-shell atomic ionization.…”

mentioning

confidence: 99%

Coplanar asymmetric (e, 2e) measurements of ionization of N₂O

Cavanagh

Lohmann

1999

Electron impact ionization of the valence 2π and inner valence 4σ orbitals of nitrous oxide, N 2 O, has been investigated using the (e, 2e) technique. The experiments have been performed in the asymmetric coplanar geometry, with a view to elucidating the dynamics of the ionization process. An incident energy of approximately 900 eV was used, with an ejected electron energy of 25 eV and scattering angles ranging from 2 • to 10 • . The kinematics for a scattering angle of 10 • correspond to bound Bethe ridge conditions, and at this angle the measured cross section exhibits a deep minimum in the binary direction, similar to that observed in atomic p-orbital ionization. The valence orbital cross sections have larger recoil intensity than is the case for atomic ionization under similar kinematics, while for ionization of the inner valence 4σ orbital, the recoil structure is somewhat smaller than has been observed for inner-shell ionization of atoms.

“…Very little experimental data on (e, 2e) studies of inner-shell ionization have been published. To date, the published results include (e, 2e) studies of the dynamics of the inner-shell ionization process by Lahmam-Bennani et al (1984), Stefani et al (1986), Bickert et al (1991), Zhang et al (1992) and Avaldi et al (1993) on rare-gas targets and Avaldi et al (1990) on a molecular target. Additionally, electron momentum spectroscopy (EMS) studies of the core electronic structures of molecules have been reported by Barathi et al (1991).…”

mentioning

confidence: 99%

“…The dynamical studies of inner-shell ionization in neon, argon (Bickert et al 1991, Zhang et al 1992, Lahmam-Bennani et al 1984 and xenon (Avaldi et al 1993) revealed a number of interesting features of the scattering which were distinctly different to outershell ionization. The most noticeable feature was the presence, at a number of energies and scattering angles, of a large recoil peak in the triple differential cross section (TDCS).…”

mentioning

confidence: 99%

An (e, 2e) investigation of inner-shell ionization in argon

Cavanagh¹,

Lohmann²

1997

New experimental results are presented of relative triple differential cross sections for ionization of the 2p orbital in argon. Coplanar asymmetric kinematics were employed in the measurements, with an incident electron energy of around 1000 eV and ejected electron energies well below the binding energy of the 2p orbital. The results indicate the presence of a dominant recoil structure in the cross section. A comparison is made with distorted-wave Born approximation calculations and the theoretical results are found to be in very good agreement with the experimental data.