表面对氢负离子在梯度电场中光剥离的调控研究

Control of the photodetachment of H^-in a gradient electric field by an elastic surface

利用闭合轨道理论对氢负离子体系在梯度电场和弹性表面附近的光剥离进行了研究,重点探讨了弹性表面对氢负离子在梯度电场中光剥离截面的影响.研究结果表明,氢负离子体系在梯度电场和弹性表面附近的光剥离与弹性表面的位置有关.当弹性表面距离氢负离子的距离比较远时,弹性表面对光剥离截面的影响较小,光剥离截面和只有梯度电场时的截面基本吻合;但是随着弹性表面到氢负离子距离的减小,弹性表面的影响越来越明显,光剥离截面的振荡振幅越来越大.除此之外,我们还对弹性表面位于Z>0的空间和位于Z<0的空间的情况进行了比较.结果表明,当弹性表面到氢负离子之间的距离给定时,弹性表面位于Z<0的空间时的光剥离截面的振荡要比位于Z>0的空间的情况要复杂.因此,我们可以通过调整弹性表面的位置对氢负离子在梯度电场中的光剥离进行调控研究.本文的研究对于理解负离子体系在非匀强电场和表面附近的光剥离可以提供一定的参考价值.

The photodetachment of H- in a gradient electric field near an elastic surface has been studied on the basis of the closed-orbit theory, especially, the influence of the elastic surface on the photode- tachment cross section of H- in a gradient electric field is discussed. It is demonstrated that the photo- detachment of H in a gradient electric field near an elastic surface is related to the position of the elastic surface. If the elastic surface was set far away from H- , it has a minor influence on the photodetach- ment cross section and the cross section approximates to that of photodetachment of H- in a gradient e- lectric field without the elastic surface. However, with the decrease of the ion-surface distance, its in- fluence becomes apparent, the oscillating amplitude of the photodetachment cross section becomes lar- ger. Besides, we compare the cases when the elastic surface lies in the Z〉0 space and in the Z〈0 space. The results suggests that the oscillatiory structure becomes more complex when elastic surface lies in the Z〈0 space rather than in the Z〉0 space. Therefore, we can control the photodetachment of H- in a gra- dient electric field by changing the position of the elastic surface. We hope that our results will be useful in understanding the photodetachment process of negative ions in non-uniform field near surfaces.