碰撞阈值下氩原子非次序双电离

利用三维经典系综模型研究了碰撞阈值下氩原子的非次序双电离.计算结果表明,关联电子末态纵向动量主要分布在二、四象限,且在原点附近几乎没有分布;Ar²⁺离子末态纵向动量谱在零动量附近呈单峰结构.上述结果与实验结果 定量一致.轨迹分析表明,在碰撞阈值下,氩原子非次序双电离的微观物理机理在不同激光强度下是不相同的.当激光强度I=0.7×10¹⁴ W/cm²时,一次碰撞主导重碰撞过程.而当I=0.4×10^{14关键词： 非次序双电离 库仑引力 碰撞阈值 电子关联}

Nonsequential double ionization of argon atom below the recollision threshold

Nonsequential double ionization (NSDI) of Ar atom below the recollision threshold is investigated using the three-dimensional classical ensembles. The calculated results reveal a dominance of events for electron emission into opposite hemispheres, a clear minimum of the correlated electron-electron momentum distributions at the origin and a single peak structure of the Ar²⁺ ions longitudinal momentum spectra near zero momentum. The momentum spectra of the Ar²⁺ ions agree with the experimental results 101 053001 (2008)] quantitatively. Trajectory back analyses show that the microscopic physical mechanisms of Ar NSDI are distinct for different intensities of the laser. When laser intensity equal to 0.7×10¹⁴ W/cm², one recollision dominates the process of the recollision. However,the domination convert to multiple recollisions as the laser intensity decreases to 0.4×10¹⁴ W/cm². In addition, the Coulomb attraction between the ion and electron plays an important role in microscopic dynamics of the electron in the process of Ar NSDI and eventually influences the final-state correlated electron-electron momentum distributions strongly.