Momentum space analysis of multiphoton double ionization of helium by intense attosecond xuv pulses.
Momentum space analysis of multiphoton double ionization of helium by intense attosecond xuv pulses.
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DOI：
10.1364/oe.18.008976
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发表时间：
2010-04
期刊：
影响因子：
3.8
通讯作者：
Zheng Zhang;Liang-You Peng;Q. Gong;T. Morishita
中科院分区：
文献类型：
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作者：
Zheng Zhang;Liang-You Peng;Q. Gong;T. Morishita
基于二维模型，研究了强阿秒XUV脉冲作用下He原子多光子双电离过程中两个电子的动量和能量分布。两种不同的模式的动量分布被确定，分别对应于不相关和相关的通道。我们对电子相关性的分析重点关注不同脉冲持续时间和脉冲后不同时间延迟的双光子和三光子双电离过程。对于双光子和三光子的情况下，一个明确的相关谷的能量分布被发现时，两个电子被弹射在相反的方向。这主要归因于第一个电子电离过程中的电子关联，我们还发现当两个电子向同一方向射出时，它们的库仑排斥对位置化阶段的电子能量分布有重要影响。最后，在三光子双电离情况下，我们观察到库仑排斥效应变得更加复杂，在能量分布中观察到一种新的追赶碰撞现象。
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.