中文摘要：

本文利用三维经典系综模型研究了低强度周期量级脉冲驱动排列分子的非次序双电离.结果表明,电子对的关联特性强烈地依赖于分子的排列方向和激光脉冲的载波包络相位;垂直分子反关联电子对的比例总是高于平行分子反关联电子对的比例;当载波包络相位从0到π逐渐增加时,反关联电子对的数目先增加再减少;对于平行分子,电子对的释放总是以正关联为主;而垂直分子的主导关联模式则依赖于激光脉冲的载波包络相位,当载波包络相位为0.3π—0.7π之间时,电子对以反关联释放为主,其他相位下以正关联为主.本文利用分子势能曲线和电子返回能量很好地解释了电子关联特性对分子排列方向和载波包络相位的依赖关系.

英文摘要：

Using the three-dimensional classical ensemble model, nonsequential double ionization（NSDI） of aligned molecules by the few-cycle laser pulse at the low intensity is investigated. Here the two electrons involved in NSDI finally are ionized through a transition doubly excited state induced by the recollision. The results show that the electron correlation behavior in NSDI is strongly dependent on the molecular alignment and the carrier-envelope phase（CEP） of the laser pulse. There are more anti-correlated emissions for the perpendicular molecules than those for the parallel molecules regardless of CEP. The dependence of the electron correlation behavior on molecular alignment can be well explained by the potential energy curves of molecules. That is because the suppressed potential barrier for perpendicular molecules is higher and the electron is more difficult to ionize than for parallel molecules. Thus for perpendicular molecules the ionization of the two electrons has longer time delay, which results in more anticorrelated emissions. Additionally, because the potential barrier for the perpendicular molecules is higher than that for the parallel molecules, the ionization yield of NSDI is about an order of magnitude smaller than that for the parallel molecules. With CEP increasing from 0 to π,the anti-correlated emission first increases and then decreases. For parallel alignment, the correlated emission is always dominant at all CEPs. However, for perpendicular alignment, the dominant correlation behavior depends on the CEP of the laser pulse. When the CEP is in a range from 0.3π to 0.7π, the anti-correlated emission is dominant. At other CEPs,the correlated emission is dominant. The dependence of the electron correlation behavior on the CEP of the laser pulse is well explained by the dependence of the returning energy of the electron on the CEP of the laser pulse. For different CEPs, the single ionization times resulting in NSDI and the corresponding acceleration electric field are different, which le