Browsing Bergen Open Research Archive by Author "Nepstad, Raymond"

Now showing items 1-6 of 6

    • 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 ...

    • Mind the gap – Relevant design for laboratory oil exposure of fish as informed by a numerical impact assessment model 

      Frøysa, Håvard Guldbrandsen; Nepstad, Raymond; Meier, Sonnich; Donald, Carey; Sørhus, Elin; Bockwoldt, Mathias; Carroll, JoLynn; Vikebø, Frode Bendiksen (Journal article; Peer reviewed, 2023)
      Laboratory experiments provide knowledge of species-specific effects thresholds that are used to parameterize impact assessment models of oil contamination on marine ecosystems. Such experiments typically place individuals ...

    • Modelling and validation of polycyclic aromatic hydrocarbons emissions from offshore oil production facilities 

      Aghito, Shankar Manuel; Pampanin, Daniela Maria; Nepstad, Raymond; Hole, Lars Robert; Breivik, Øyvind (Journal article; Peer reviewed, 2024)
      The development of numerical models for investigating the risks and impact caused by human activities to the marine environment is important. Herein, the recently developed ChemicalDrift Lagrangian dispersion model was ...

    • 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. ...