TY - JOUR T1 - Non-Sequential Double Ionization of $CO_2$ Molecule and Kr Atom in Linearly Polarized Laser Fields AU - Song , Kaili AU - Tian , Yanrong AU - Ben , Shuai AU - Xu , Tongtong AU - Zhang , Hongdan AU - Liu , Xue-Shen AU - Guo , Jing JO - Journal of Atomic and Molecular Sciences VL - 1 SP - 1 EP - 4 PY - 2017 DA - 2017/08 SN - 8 DO - http://doi.org/10.4208/jams.050817.072517a UR - https://global-sci.org/intro/article_detail/jams/10428.html KW - -- AB -

Using two-dimensional classical ensemble method, a theoretical study of non-sequential double ionization (NSDI) with Krypton (Kr) and carbon dioxide $(CO_2)$ is presented at different laser intensities. The numerical results show that the probability for NSDI of Kr atom is higher than that of $CO_2$ molecule. Moreover, for the same laser intensity, the momentum correlation spectrum of $CO_2$ molecule is drastically different from Kr atom. For example, for the laser intensities $I = 0.065 PW ⁄ cm^2$ and $I =0.15 PW ⁄ cm^2,$ the correlation spectrum of $CO_2$ molecule tends to distribute in the first and third quadrants, and presents a "finger-like" structure. However, for Kr atom at $I = 0.065 PW ⁄ cm^2,$ the emitted electrons pairs tend to distribute in the second and fourth quadrants; When the laser intensity increases to $0.15PW ⁄ cm^2,$ the two electrons mainly distribute in the first and third quadrants and along two distinct lines being paralleled to the diagonal. In addition, our numerical calculations reveal that this different phenomenon is closely related to the Coulomb focusing effect: Coulomb potential will attract the returning electron more dramatically when it moves near the atomic or molecular core. For $CO_2$ molecule, the returning electron is dramatically attracted by three cores, so the returned electron of $CO_2$ molecule possesses higher energy than Kr atom does.