Obtaining the highest molecular orbital peak of organic matter from photoelectron yield spectra
Obtaining the highest molecular orbital peak of organic matter from photoelectron yield spectra
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从光电子产率光谱中获取有机物的最高分子轨道峰
DOI：
10.1103/physrevapplied.11.054081
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
Hisao Ishii and Peter Krueger
中科院分区：
文献类型：
--
作者：
Shohei Tadano;Yasuo Nakayama;Hiroumi Kinjo;Hisao Ishii and Peter Krueger
我们提出了一种基于态密度近似和通用传输函数和损耗函数的简单光电子产率谱（PYS）理论。该理论再现了金属和半导体在间接跃迁状态下的已知阈值行为。我们表明，高斯形态密度导致 PYS 谱的增加非常接近阈值能量的三次方，这表明有机物 PYS 的经验立方定律反映了高斯展宽的最高占据分子轨道峰。我们展示了如何从 PYS 谱中提取峰位置和宽度。几种有机化合物获得的结果与紫外光电子发射数据非常吻合。我们进一步表明，占据态的密度大约与近阈值区域中 PYS 谱的二阶导数成正比。
We propose a simple theory of photoelectron yield spectra (PYS) on the basis of a density-of-states approximation and universal transmission and loss functions. The theory reproduces the known threshold behavior of metals and that of semiconductors in the indirect-transition regime. We show that a Gaussian-shaped density of states leads to a PYS spectrum that increases very nearly as the third power of energy from threshold, indicating that the empirical cube law of PYS of organic matter reflects the Gaussian-broadened highest occupied molecular orbital peak. We show how the peak position and width can be extracted from the PYS spectrum. The results obtained for several organic compounds agree well with ultraviolet photoemission data. We further show that the density of occupied states is approximately proportional to the second derivative of the PYS spectrum in the near-threshold region.