Charge transfer in hyperthermal energy collisions of Li+ with alkali-metal-covered Cu(001) .1. Dynamics of charge state formation

被引:51
作者
Behringer, ER
Andersson, DR
Cooper, BH
Marston, JB
机构
[1] CORNELL UNIV, ATOM & SOLID STATE PHYS LAB, ITHACA, NY 14853 USA
[2] BROWN UNIV, DEPT PHYS, PROVIDENCE, RI 02912 USA
来源
PHYSICAL REVIEW B | 1996年 / 54卷 / 20期
关键词
D O I
10.1103/PhysRevB.54.14765
中图分类号
T [工业技术];
学科分类号
08 ;
摘要
We have measured the charge state fractions in the scattered flux versus the work-function change induced by Cs adsorbates when hyperthermal energy Li+ ions are incident on Cs/Cu(001). As the work function phi decreases from its clean surface value (phi=4.59 eV), the positive ion fraction decreases from 0.64 to less than a few percent, while the negative ion fraction slowly increases from less than a few percent to 0.14 at the lowest work function attained (phi=1.29 eV). Theoretical calculations based on a many-body solution to the time-dependent, multiple-state, Anderson-Newns model of resonant charge transfer qualitatively reproduce the observed trends. Detailed examination of the calculations shows that the theoretically predicted dependence of the final charge state fractions on work function and the dynamics of the charge-transfer process are both strongly influenced by the wave function of the ion-surface system when the incident ion is close to the surface and also by the changing relationships between the relevant time and energy scales as the scattered particle moves away from the surface.
引用
收藏
页码:14765 / 14779
页数:15
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