Dielectric Constant of Ionic Solutions: A Field-Theory Approach
Dielectric Constant of Ionic Solutions: A Field-Theory Approach
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DOI：
10.1103/physrevlett.108.227801
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发表时间：
2012-05-29
影响因子：
8.6
通讯作者：
Orland, Henri
中科院分区：
文献类型：
--
作者：
Levy, Amir;Andelman, David;Orland, Henri
我们研究的介电液体（例如水）的介电响应的变化时，盐被添加到溶液中。采用场论方法，我们展开的吉布斯自由能的一阶环展开和计算自洽的介电常数。我们解析地预测了介电衰减，它依赖于离子强度在一个复杂的方式。此外，水化壳的定性描述被发现，其特征在于由一个单一的长度尺度。我们的预测很好地适合了大范围的浓度不同的盐，只使用一个适合的参数有关的离子和偶极子的大小。
We study the variation of the dielectric response of a dielectric liquid (e.g. water) when a salt is added to the solution. Employing field-theoretical methods, we expand the Gibbs free energy to first order in a loop expansion and calculate self-consistently the dielectric constant. We predict analytically the dielectric decrement which depends on the ionic strength in a complex way. Furthermore, a qualitative description of the hydration shell is found and is characterized by a single length scale. Our prediction fits rather well a large range of concentrations for different salts using only one fit parameter related to the size of ions and dipoles.