关于热电子发射理论的评述(Ⅱ)——单原子层和偶极子理论

本文对热电子发射中应用单原子层和偶极子理论作了分析和批判。我们认为:1.单原子层的存在不是无条件的,它与基底的温度、结构、纯度和外界真空度都有关系;2.关于时而能、时而又不能观察到的电子发射峰值,是一个有待于进一步明确的现象,不能简单地用单原子层和偶极子理论来解释;3.吸附了外界原子或分子使电子发射增加的事实,并不是由于偶极矩降低了基底的逸出功,发射的电子来源于被吸附物质的价电子;4.实验证明“L”阴极是Ba-O-W系统,它既不是单原子层,也不是单分子层,也不适用偶极子理论。

HEORY OF THERMIONIC EMISSION (II)——ON THE MONOATOMIC LAYER AND DIPOLE THEORY

The present paper is a criticism of the application of the monoatomic layer and simple dipote theory to thermionic emission. We have come to the following conclusions: (1) the existence of the monoatomic layer is conditional, it depends upon the temperature, surface structure and purity of the substrate as well as upon the vacuum environment; (2) the appearance, and sometimes disappearance, of the emission peaks is a problem for further study, and it can not be explained simply by the monoatomic layer and dipole theory; (3) the enhanced emission after adsorption of foreign atoms or molecules is not due to the formation of dipoles which lower the work function of the substrate, but comes from the valence electrons of the adsorbate, and (4) the "L" cathode is a Ba-O-W system, neither monoatomic nor monomolecular, and the dipole theory is not applicable here.