On the conception of electrical potential difference between two phases. II
On the conception of electrical potential difference between two phases. II
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DOI：
10.1021/j150313a014
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发表时间：
1930-07-01
影响因子：
--
通讯作者：
Guggenheim, EA
中科院分区：
文献类型：
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作者：
Guggenheim, EA
两相电位差154I与(i)相同。尽管如此，他还是相当重视将X分解为化学项µ和电学项的总和。作者希望在这篇文章中修改他以前的文章中提出的原则，使之符合布朗斯特德的观点。例如，让我们考虑在没有任何外场的情况下，一块铜和一块锌在电子方面处于平衡状态，让我们忽略金属离子和原子相对缓慢的相互扩散。电子的分布将使它们在两相中的电化学电位相同。然而，这种平衡的描述并没有告诉我们铜和锌之间电子分布的不对称性。即使两种金属在大小、形状和相对位置上完全对称，它们所带的电荷一般也不会相同。电荷的实际分布既取决于两种金属的固有特性，也取决于它们的大小、形状和相对位置。因此，问题是是否存在某种与两块金属的大小、形状和相对位置无关的平衡电荷分布的函数。这样的函数确实存在，现在将被定义。让我们想象两个几何表面的大小、形状和两块金属的相对位置，并考虑“电”在每个表面的分布，使得任何体积较大的元素（与原子相比）的平均电荷密度与每个金属中相应元素的平均电荷密度相同。任何体积单元上的平均密度都是零，除非该单元位于其中一个表面的邻域中。从这个假设的电分布中，人们可以计算出在任何一点的静电势，假设整个介质常数是统一的。我们会发现，这样计算出来的静电势，除了在表面附近，在每一种金属所对应的整个体积内，都是恒定的。此外，由此计算出的对应于铜的表面内点与对应于锌的表面内点的静电势之差将与尺寸无关。
ELECTRICAL POTENTIAL DIFFERENCE BETWEEN TWO PHASES 154I identical with (i). He nevertheless attaches considerable importance to the decomposition of X into the sum of a chemical term µ and an electrical term. The author wishes in the present paper so to modify the principle put forward in his former paper as to fall into line with the point of view7 of Bronsted.Let us consider, for example, a piece of copper and a piece of zinc in equilibrium as regards electrons in the absence of any external field and let us ignore the comparatively slow interdiffusion of the metallic ions and atoms. The electrons will be so distributed that their electrochemical potential is the same in both phases. This description of the equilibrium however tells us nothing about the asymmetry in the distribution of the electronsbe-tween the copper and the zinc. Even if there is complete symmetry between the two metals as regards size, shape, and relative position, the electric charge on each will generally not be the same. The actual distribution of charge will depend both on the intrinsic properties of the two metals andalso on their sizes, shapes and relative positions. The question therefore suggests itself whether there is not some function of the equilibrium charge distribution, which is independentof the size, shapeand relative positions of the two pieces of metal. Such a function does exist and will now be defined. Let us imagine two geometrical surfaces of the size, shapeand relative positions of the twopieces ofmetal and consider a distribution of “elec-tricity” within each of these surfaces such that the mean electric charge density over any element of volume, large compared with an atom, is the same as that within the correspondingelement in each of the metals. The mean density over any volume element will incidentally be zero unless the element be in the neighborhood of one of the surfaces. From this hypothetical distribution of electricity one might calculate the electrostatic potential at any point, on the assumption of a dielectric constant unity throughout. It would be found that the electrostatic potential, so calculated, would be constant throughout the volume corresponding to each metal, except in the neighbourhood of the surface. Moreover the difference in the electrostatic potential thus calculated for a point within thesurface corresponding to the copper and that for a point within the surface corresponding to the zinc, will be independent of the size,