碰撞阈值下氩原子非次序双电离  

Nonsequential double ionization of argon atom below the recollision threshold

作　　者：张东玲[1] 汤清彬[1] 余本海[1] 陈东[1] 

机构地区：[1]物理电子工程学院信阳师范学院,信阳464000

出　　处：《物理学报》2011年第5期231-238,共8页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:11005088);河南省科技计划项目(批准号:082300410050;102300410241);河南省高等学校青年骨干教师资助计划项目;河南省教育厅自然科学研究计划项目(批准号:2009A140006)资助的课题~~

摘　　要：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[Phys.Rev.Lett.101053001(2008)]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=0.7×1014W/cm2时,一次碰撞主导重碰撞过程.而当I=0.4×1014W/cm2时,多次碰撞占主导.另外,离子与电子之间的库仑引力,在氩原子非次序双电离过程中具有重要的作用,对电子的微观动力学行为有很大的影响,并最终影响关联电子末态动量分布.Nonsequential double ionization（NSDI） of Ar atom below the recollision threshold is investigated using the threedimensional 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 [Phys.Rev.Lett.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.

关 键 词：非次序双电离 库仑引力 碰撞阈值 电子关联 

分 类 号：O562.4[理学—原子与分子物理]