Localization of excess electrons in dense polar vapors
Localization of excess electrons in dense polar vapors
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稠密极性蒸汽中多余电子的局域化
DOI：
10.1021/j150661a003
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发表时间：
1984
期刊：
影响因子：
--
通讯作者：
P. Krebs
中科院分区：
文献类型：
--
作者：
P. Krebs
我们讨论了稠密的亚和超临界极性蒸汽（NH3，H20）中的电子迁移率作为蒸汽密度和温度的函数。它们表现出从准自由态到局域电子态的转变。观察到这种转变开始的密度服从Ioffe-Regel规则。它可以证明由一个变分法的Luttinger，在这个密度的取向波动的形成变得重要的电子局域化。光电子发射实验，以确定在蒸汽中的电子注入水平表明，依赖于入射光的能量，注入到极性介质中的电子不仅发生到导带，而且到预先存在的陷阱状态。这些额外的信息允许定性讨论的电子传输过程，包括所涉及的电子状态。随着氨蒸气密度的增加，实验观察到的电子迁移率在蒸气的临界密度附近显示出异常的密度依赖性。在此密度范围内，还发生了进一步的转变：局域在致密取向团簇中的电子转变为局域在空穴中的电子（溶剂化电子）。
We discuss electron mobilities in dense sub-and supercritical polar vapors (NH3, H20) as a function of vapor densityand temperature. They show a transition from the quasi-freeto the localized electron state. The density where the onset of this transition is observed obeys the Ioffe-Regel rule. It can be demonstrated by a variational method of Luttinger that at this density the formation of orientational fluctuations becomes important for electron localization. Photoemission experiments in order to determine the electron injection level in the vapor show that, dependent on the energy of the incident light, injection of electrons into the polar medium occurs not only into the conduction band but also into preexisting trap states. This additional information allows a qualitative discussion of the electron transport process including the involved electron states. With increasing ammonia vapor density the experimentally observed electron mobility shows an anomalous density dependence around the critical density of the vapor. It is concluded that in this densityrange a further transition occurs: The electron localized in a dense orientational cluster turns into an electron localized in a cavity (solvated electron).