Many-body theory of charge transfer in hyperthermal atomic scattering.
Many-body theory of charge transfer in hyperthermal atomic scattering.
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超热原子散射中电荷转移的多体理论。
DOI：
10.1103/physrevb.48.7809
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发表时间：
1992
期刊：
影响因子：
--
通讯作者：
Richardson
中科院分区：
文献类型：
--
作者：
Marston;Andersson;Behringer;Cooper;DiRubio;Kimmel;Richardson
我们使用Newns-Anderson哈密顿量来描述当超高温碱金属原子从金属表面散射时发生的多体电子过程。在Brako和Newns之后，我们将电子多体波函数扩展到粒子-空穴对的数量（我们将项保留到并包括单个粒子-空穴对）。我们扩展了他们早期的工作，包括能级交叉，激发中性粒子和负离子。完整的运动方程集的数值积分，没有进一步的近似，以获得作为时间的函数的多体振幅。对离子电荷分布和激发态原子占有率等终态量与速度和功函数的关系进行了实验比较。特别是，在5- 1600 eV能量范围内，从清洁的Cu（001）表面散射碱金属离子的实验定量地限制了理论。Na[sup +]离子的中和几率在中等速度下有一个极小值，与理论一致。这一行为与K[sup +]和Li[sup +]形成对比，K[sup +]几乎没有中和作用，Li[sup +]的中性分数随着速度的降低而单调增加。在碰撞事件的一小部分期间，粒子-空穴激发被留在金属中;预计这种耗散的能量相当小（大约十分之一电子伏特）。事实上，经典的轨道模拟的表面动力学帐户以及观察到的能量损失，从而提供了一些理由，我们截断的运动方程在单粒子-空穴对水平。Li[sup +]散射实验低功函数表面提供定性信息的重要性，多体效应。在足够低的功函数下，实际上观察到了预测会出现的负离子。«少
We use the Newns-Anderson Hamiltonian to describe many-body electronic processes that occur when hyperthermal alkali atoms scatter off metallic surfaces. Following Brako and Newns, we expand the electronic many-body wave function in the number of particle-hole pairs (we keep terms up to and including a single particle-hole pair). We extend their earlier work by including level crossings, excited neutrals, and negative ions. The full set of equations of motion is integrated numerically, without further approximations, to obtain the many-body amplitudes as a function of time. The velocity and work-function dependence of final-state quantities such as the distribution of ion charges and excited atomic occupancies are compared with experiment. In particular, experiments that scatter alkali ions off clean Cu(001) surfaces in the energy range 5--1600 eV constrain the theory quantitatively. The neutralization probability of Na[sup +] ions shows a minimum at intermediate velocity in agreement with the theory. This behavior contrasts with that of K[sup +], which shows virtually no neutralization, and with Li[sup +], which exhibits a monotonically increasing neutral fraction with decreasing velocity. Particle-hole excitations are left behind in the metal during a fraction of the collision events; this dissipated energy is predicted to be quite small (on themore » order of tenths of an electron volt). Indeed, classical trajectory simulations of the surface dynamics account well for the observed energy loss, and thus provide some justification for our truncation of the equations of motion at the single particle-hole pair level. Li[sup +] scattering experiments off low work-function surfaces provide qualitative information on the importance of many-body effects. At sufficiently low work function, the negative ions predicted to occur are in fact observed.« less