利用多体玻姆力学方法研究电子再碰撞过程对原子非序列双电离电离机制的影响

Non-sequence double ionization is a hot issue in the field of strong field physics. There are two main mechanisms:the "recollision-impact-ionization" mechanism and the "recollision-subsequent-ionization" mechanism. A recollision process is involved in the two mechanisms and it is critical to studying the ionization mechanism.As a result,the dynamics details of the re-collision resulting from two ionization mechanisms are difficult to be clearly exhibited through quantum mechanics.This project intends to solve this problem by using the multi-body Bohmian mechanics method. 1) For the recollision process,we design a physical model of the collision of the continuous state wave packet with ground state wave packet,which is used to simulate the collision process of ionized electrons coming back to the vicinity of the parent nucleus when the direction of laser field is reversed; 2) By changing the atomic Coulomb parameter, the softened Coulomb parameter between the two electrons, and the kinetic energy of the recollision wave packet, and combining the trajectory and energy of the corresponding Bohmian particles, we carry put the analysis aiming at clarify which condition causes the two ionization mechanisms in the non-sequence double ionization and how it affects mechanism. The in-depth study of the non-sequence double ionization mechanism under different physical conditions provides a theoretical support for people to deeply understand the non-sequence double ionization process and electron correlation problems, and then manipulate microscopic atomic electrons.

非序列双电离是强场物理领域里的热点问题，主要存在两种电离机制，分别为“返回-硬碰-电离”机制与“返回-激发-电离”机制。这两种机制都涉及再碰撞过程，再碰撞过程对于研究电离机制至关重要，而涉及到两种电离机制的再碰撞动力学细节很难通过量子力学方法给出清晰的展示。基于此问题，本项目拟采用多体玻姆力学方法来处理。1）针对再碰撞过程，我们设计了连续态波包与基态波包碰撞的物理模型，用来模拟在激光场反向时电离电子回到母核附近的碰撞过程；2）分别改变原子库伦软化参数、两电子库伦软化参数及再碰撞波包的动能，结合对应的玻姆粒子的轨迹、能量进行分析，阐明以上哪些条件对原子非序列双电离的两种电离机制产生影响以及如何影响。对在不同物理条件下非序列双电离电离机制的深入研究，为人们深入理解非序列双电离过程及电子关联问题，进而操控微观的原子电子提供了理论支持。

多体玻姆力学方法被用来研究一维氙原子中两个电子在强场中的再碰撞过程。我们集中研究了基态概率、复合波包动能和原子库仑参数对非次序双电离过程的影响。 伴随着复合玻姆粒子能量的降低，离子势阱的变浅，以及单电离态概率的增加，非次序双电离的概率也随之增加。对于非次序双电离概率的增加，基态概率的减少尤为重要。当基态概率较高时，由于强量子力的作用，复合粒子被原子核捕获，而这种量子力是由复合电子和其基态之间的干涉产生。