• Direct two-photon double ionization of H2 

      Simonsen, A. S.; Sørngård, Stian Astad; Nepstad, Raymond; Førre, Morten (Peer reviewed; Journal article, 2012-06-05)
      We have studied the process of direct (nonsequential) two-photon double ionization of molecular hydrogen (H2). Solving the time-dependent Schr¨odinger equation by an ab initio method, total (generalized) and singledifferential ...
    • Multiphoton ionization and stabilization of helium in superintense xuv fields 

      Sørngård, Stian Astad; Askeland, Sigurd; Nepstad, Raymond; Førre, Morten (Peer reviewed; Journal article, 2011)
      Multiphoton ionization of helium is investigated in the superintense field regime, with particular emphasis on the role of the electron-electron interaction in the ionization and stabilization dynamics. To accomplish this, ...
    • Stabilization of circular Rydberg atoms by circularly polarized infrared laser fields 

      Askeland, Sigurd; Sørngård, Stian Astad; Pilskog, Ingjald; Nepstad, Raymond; Førre, Morten (Peer reviewed; Journal article, 2011-09-29)
      The ionization dynamics of circular Rydberg states in strong circularly polarized infrared (800 nm) laser fields is studied by means of numerical simulations with the time-dependent Schr¨odinger equation. We find that at ...
    • Two-photon double ionization of helium by attosecond laser pulses: Evidence of highly correlated electron motion 

      Askeland, Sigurd; Nepstad, Raymond; Førre, Morten (Peer reviewed; Journal article, 2012)
      We apply a recently developed ab initio numerical framework to investigate the angular distributions of the emitted electrons in the immediate proximity of the threshold for the two-photon double ionization of helium. ...