Blar i Bergen Open Research Archive på forfatter "Askeland, Sigurd"
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Correlated ionization processes in atoms and molecules
Askeland, Sigurd (Doctoral thesis, 2013-09-27)This thesis is composed of five scientific papers written between 2009 and 2013. The focus of this work is on various photo-ionization processes in small atoms and molecules. The strong field phenomenon called “atomic ... -
Dynamics in the H2+ molecule, using a one dimensional model
Askeland, Sigurd (Master thesis, 2009-06-02)A 1D model of the hydrogen molecular ion in the Born-Oppenheimer (BO) approximation. The making and testing of the model is described, as well as some underlying theory. The model also calculates non-BO effects. -
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, ... -
Probing two-center interference in H2+ using chirped pulses
Askeland, Sigurd; Førre, Morten (Peer reviewed; Journal article, 2013)The influence of intermediate resonant dissociative channels in the few-photon ionization dynamics of H+2 is demonstrated in a pump-probe scenario. Two-photon ionization of H+2 by two sequentially applied pump and probe ... -
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. ...