title: Mechanisms of photo double ionization of helium by 530 eV photons.
abstract: We have measured fully differential cross sections for photo double ionization of helium 450 eV above the threshold. We have found an extremely asymmetric energy sharing between the photoelectrons and an angular asymmetry parameter beta approximately 2 and beta approximately 0 for the fast and slow electrons, respectively. The electron angular distributions show a dominance of the shakeoff for 2 eV electrons and clear evidence of an inelastic electron-electron scattering at an electron energy of 30 eV. The data are in excellent agreement with convergent close-coupling calculations.
authors.affiliation: Institut für Kernphysik, Universität Frankfurt, August-Euler-Strasse 6, D-60486 Frankfurt, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Knapp
authors.forename: A
authors.initials: A
authors.lastname: Kheifets
authors.forename: I
authors.initials: I
authors.lastname: Bray
authors.forename: Th
authors.initials: T
authors.lastname: Weber
authors.forename: A L
authors.initials: AL
authors.lastname: Landers
authors.forename: S
authors.initials: S
authors.lastname: Schössler
authors.forename: T
authors.initials: T
authors.lastname: Jahnke
authors.forename: J
authors.initials: J
authors.lastname: Nickles
authors.forename: S
authors.initials: S
authors.lastname: Kammer
authors.forename: O
authors.initials: O
authors.lastname: Jagutzki
authors.forename: L Ph H
authors.initials: LP
authors.lastname: Schmidt
authors.forename: T
authors.initials: T
authors.lastname: Osipov
authors.forename: J
authors.initials: J
authors.lastname: Rösch
authors.forename: M H
authors.initials: MH
authors.lastname: Prior
authors.forename: H
authors.initials: H
authors.lastname: Schmidt-Böcking
authors.forename: C L
authors.initials: CL
authors.lastname: Cocke
authors.forename: R
authors.initials: R
authors.lastname: Dörner