The mobility of ions in pure gases
The mobility of ions in pure gases
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DOI：
10.1098/rspa.1930.0149
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发表时间：
1930-09-01
期刊：
影响因子：
--
通讯作者：
Powell, CF
中科院分区：
文献类型：
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作者：
Tyndall, AM;Powell, CF
虽然在过去的30年里，人们几乎不断地测定气体中离子的迁移率，但离子的性质仍然不清楚。不同的实验所获得的值，使用各种方法，相差的数量远远超过那些被归因于观测误差和一些方法产生的结果是复杂的，难以解释的任何简单的理论的性质的离子。从大量实验数据中得出的主要事实在《气体中的电传导》一书中作了概括。似乎很可能在迄今为止所做的实验中，所研究的气体都不是光谱纯的。在许多情况下，硬橡胶和硫磺等材料与气体接触。在其他情况下，该设备已通过涂蜡法兰或润滑脂接头进行气密性处理。在这种条件下，气体的纯度还很不理想.它不断受到杂质的污染，例如来自容器壁和设备金属部件的水蒸气和二氧化碳，以及来自蜡、硬质橡胶等的蒸气。这些杂质可能对电子具有很大的亲和力，并可能与正离子结合形成基团。在这样的条件下，在给定的气体中，离子很可能由团簇组成，团簇的大小和质量随实验的不同而不同。为什么许多观察者发现负离子是分子量级的，而不是氮、氢等中的电子，这一点是显而易见的，因此，在假定离子是单分子的情况下，所发现的实际迁移率小于从气体的经典动力学理论的观点所计算出的迁移率，这并不奇怪。例如，本文作者发现，在600毫米汞柱压力下的氮气实验中，将其新鲜引入钟罩下的装置中，负载流子由离子和电子的混合物组成。来自壁的污染的影响清楚地表现在这样的事实上，即在将气体留在装置中过夜时，“正常”离子的数量增加，而电子的数量减少。
Although determination of the mobility of ions in gases have been made Almost continuously during the last 30 years, the nature of the ions still remains obscure. The values obtained by different experiments, using a variety of methods, differ by amounts far in excess of those to be attributed to be observational errors and some methods yield results which are complicated and difficult to explain on any simple theory of the nature of the ion. The main facts which have emerged from the mass of experimental data are summarised in “Conduction of Electricity through Gases.”* It seems probable that in none of the experiments made hitherto has the gas under examination been spectroscopically pure. In many cases materials such as ebonite and sulphur have been in contact with the gas. In others the apparatus has been made gas-tight by means of waxed flanges or greased joints. In such conditions the purity of the gas leaves much to be desired. It is continually being contamined by impurities such as water vapour and carbon dioxide coming from the walls of the vessels and from the metals parts of the apparatus as well as by the vapours from the wax, ebonite, etc. Such impurities may have large affinities for electron and may unite with the positive ions to form groups. In such conditions, in a given gas, the ions may well consist of clusters of which the size and mass vary from one experiment to another. The reason why many observers have found the negative ions to be of molecular magnitude and not electrons in nitrogen, hydrogen, etc., becomes Obvious, and it is not surprising that the actual mobilities found are smaller than those calculated theoretically from the standpoint of the classical dynamical theory of gases, assuming the ions to be monomolecular. The present writers for example, found that in an experiments on nitrogen at a pressure of 600 mm, freshly introduced into an apparatus contained under a bell jar, the negative carries consisted of a mixture of ions and electrons. The effect of the contamination coming from the walls was clearly shown by the fact that the number of “normal” ions increased, and of electrons decreased, on leaving the gas in the apparatus overnight.