Open AccessMomentum space analysis of multiphoton double ionization of helium by intense attosecond xuv pulses
Author(s) -
Zheng Zhang,
Liang-You Peng,
Qihuang Gong,
Tōru Morishita
Publication year - 2010
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.18.008976
Subject(s) - double ionization , attosecond , physics , extreme ultraviolet , electron , ionization , atomic physics , photon , momentum (technical analysis) , position and momentum space , photon energy , laser , optics , ion , ultrashort pulse , nuclear physics , quantum mechanics , finance , economics
We investigate the momentum and energy distributions of the two electrons in multiphoton double ionization of He by intense attosecond xuv pulses, based on a two-dimensional model. Two different patterns of the momentum distributions are identified, corresponding to the uncorrelated and correlated channels, respectively. Our analysis of the electron correlations focuses on two-photon and three-photon double ionization processes for different pulse durations and for different time delays after the pulses. For both two-photon and three-photon cases, a clear correlation valley in energy distributions is found when both electrons are ejected in opposite directions. This is mostly attributed to the electron correlations during the ionization of the first electron. We also find that when two electrons are ejected in the same direction, their Coulomb repulsion has an significant influence on the electron energy distributions during the postionization stage. Finally, in the case of three photon double ionization, we observe that the effects of the Coulomb repulsion become much more complicated, and a new catch-up collision phenomena is observed in the energy distributions.