H^-在金属面附近光剥离的波包动力学研究

Wave packet dynamics of the photodetachment of H^- near a metal surface

利用波包演化和自关联函数方法对H-在金属面附近光剥离的波包动力学进行了研究.结果表明,金属面附近光剥离电子的波包演化和回归结构与H-到金属面的距离、激光脉冲的脉冲宽度和初始动量都有一定的关系.因此,可以通过改变离子表面距离和激光脉冲的参数对光剥离电子的动力学性质进行调控研究.除此之外,光剥离电子的镜像态寿命对波包的演化和自关联函数也会产生一定的影响:考虑镜像态寿命的影响时,随着时间的演化,波包概率密度的振幅逐渐减小,波包整体上有明显的衰减,寿命对波包演化过程中的干涉有削弱的作用;通过对电子波包的自关联函数研究,发现无限长寿命的电子波包有很好的量子回归现象,而当考虑寿命因素后光剥离电子波包随着时间的演化会发生周期性的坍塌和扩散,经过一段时间后,该回归现象消失.本文的理论研究可以为表面附近电子波包动力学的实验研究提供一定的参考价值.

The wave packet dynamics of the photodetachment of H-near metal surface is studied by using the wave packet evolution and the autocorrelation function.The results show that the evolution and the revival structure of the detached electron depend not only on the ion-surface distance,but also on pulse width and initial pulse momentum.Therefore,we can control the wave packet dynamics of H-near a metal surface by changing the ion-surface distance and the parameter of the pulse laser.Besides,the electronic image state lifetime can also affect the wave packet evolution and the autocorrelation function.We find that with considering the electronic state lifetime,the amplitude of the quantum probability density decreases gradually with time,the whole wave packet structure has a significant attenuation and the lifetime can weaken the interference phenomenon in the process of wave packet evolution.Through the research on the autocorrelation function of electronic wave packet,we find that the wave packet exhibits a good revival structure without considering the lifetime of the state lifetime;however,with considering the lifetime of the state lifetime,the wave packet periodically collapses and expands with time,but after a period of time,the revival structure disappears.We hope that our theoretical study will provide some references for the experimental research of wave packet dynamics of negative ion near surfaces.