ANGLE-RESOLVED PHOTOEMISSION FROM MOLECULES IN INDEPENDENT-ATOMIC-CENTER APPROXIMATION
ANGLE-RESOLVED PHOTOEMISSION FROM MOLECULES IN INDEPENDENT-ATOMIC-CENTER APPROXIMATION
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DOI：
10.1103/physrevb.17.4573
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发表时间：
1978-01-01
影响因子：
3.7
通讯作者：
GROBMAN, WD
中科院分区：
文献类型：
--
作者：
GROBMAN, WD
本文讨论了取向分子光致发射的总振幅是原子中心球对称区域相干辐射振幅之和的近似的几个含义。我们表明，这种近似，这是越来越有效的高能量（可访问，例如，同步辐射源）是很容易计算使用列表的初始状态原子功能和简单的径向薛定谔方程的解决方案。我们说明了这样一个事实，即在特殊但重要的情况下（例如，定向汽油），可以获得在固定的最终能量的光电子发射的角分布，而无需任何诉诸原子光电子发射振幅计算。最后，我们强调的事实是，正交化平面波的方法，这是一个特殊的情况下，独立的原子中心近似，失败在两个方面-忽略原子的相移，并忽略初始状态的核心区域波函数的行为，这是至关重要的在高能量。后一点是通过比较正交化平面波计算使用斯莱特原子函数（强调键合区波函数行为），氢波函数，它可以有径向节点和核心区域的行为，可以更接近的行为，真正的初始状态波函数。
This paper considers several implications of the approximation that the total amplitude for photoemission from an oriented molecule is the sum of the amplitude of coherent emission from spherically symmetric regions at the atomic centers. We show that this approximation, which is increasingly valid at high energies (accessible, for example, to synchrotron-radiation sources) is readily calculable using tabulated initial-state atomic functions and simple solutions of the radial Schrödinger equation. We illustrate the fact that in special but important cases (eg, oriented benzine), one can obtain the angular distribution of photoemission at fixed final energy without any recourse to atomic-photoemission-amplitude calculations. Finally, we emphasize that fact that the orthogonalized-plane-wave approach, which is a special case of the independent-atomic-center approximation, fails in two regards—neglect of atomic phase shifts, and the neglect of initial-state core-region wave-function behavior, which is crucial at high energies. This latter point is illustrated by comparing orthogonalized-plane-wave calculations using Slater atomic functions (which emphasize the bonding-region wave-function behavior), and hydrogenic wave functions, which can have radial nodes and core-region behavior which can more closely approximate the behavior of the true initial-state wave functions.