强激光场氦原子非序列双电离过程中光子动量分配  

Photon momentum partition in non-sequential double ionization of helium under strong laser field

作　　者：陶建飞[1] 刘杰[2,3] 

机构地区：[1]中国工程物理研究院北京研究生部,北京100088 [2]北京应用物理与计算数学研究所,北京100088 [3]北京大学应用物理与技术研究中心,北京100084

出　　处：《中国科学：物理学、力学、天文学》2014年第12期1356-1362,共7页Scientia Sinica Physica,Mechanica & Astronomica

基　　金：国家重点基础研究发展计划资助项目(编号:2013CB834101)

摘　　要：本文研究了He原子非序列双电离过程中光子动量在电子和原子核间的分配问题.扩展三维半经典再散射模型使之同时包含原子核的运动,数值模拟计算原子体系的三维动力学并统计原子核与电子沿激光场传播方向的动量.结果表明,原子核与电子之间的质量差异导致电子波包向激光传播方向漂移的比核厉害,当电子靠近原子核附近而受到核的散射时,会将一部分动量传递给原子核.这种动量交换与氦原子的非序列双电离机制紧密相关:简单计算表明,序列电离机制(Sequential Double Ionization,SDI),回碰直接电离机制(Recollision Impact Ionization,RII)以及回碰激发再电离机制(RecollisionExcitation with Subsequent Ionization,RESI)会给出不同的电子动量.Partition of photon momentum between the electron and atomic core in non-sequential double ionization of helium is investigated. Semi-classical rescattering model is extended, in order to include the motion of the atomic core. Numerical simulation of the 3D dynamics of the atomic system is performed and data of momentum of the electron and atomic core along the laser propagation direction is collected for further study. Analysis shows that the wavepacket of the electron drifts much further along the laser propagation direction than the atomic core due to the enormous mass difference between them, thus the electron transmitting part of its momentum to the atomic core during rescattering. This kind of momentum exchange is closely related to the dynamics of non-sequential double ionization： a simple calculation indicates that sequential double ionization （SDI）, recollision impact ionization （RII） and recollision-exicitation with subsequent ionization （RESI） lead to very different final electron momentum.

关 键 词：光子动量 非序列双电离 半经典模型 电子关联 再散射 

分 类 号：O562[理学—原子与分子物理]