Dielectric relaxation of aqueous NaCl solutions
Dielectric relaxation of aqueous NaCl solutions
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DOI：
10.1021/jp982977k
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发表时间：
1999-01-07
影响因子：
2.9
通讯作者：
May, PM
中科院分区：
文献类型：
--
作者：
Buchner, R;Hefter, GT;May, PM
用基于矢量网络分析仪的商用介电测量系统，在0.2 ≤ v（GHz）≤ 20的频率范围内测定了氯化钠水溶液的复介电常数。在5、20、25和35 ℃下研究了0.1 ≤ nz（mol kg（-1））≤ 5（质量分数0.005 ≤ w ≤ 0.23）的NaCl溶液。本文提出了一种改进的导电样品介电测量系统的校准方法。复介电常数谱用Cole-Cole弛豫时间分布表示。在可能的情况下，将获得的拟合参数、静态介电常数epsilon和弛豫时间tau以及分布参数cr与文献数据进行比较，以评估仪器的性能，发现其与时域和波导系统的性能相当。根据NaCl浓度对体系溶解度的影响，推导出了有效溶剂化数。数据表明，除了钠离子的水分子的无旋键合，动力学去极化滑移边界条件下确定的解决方案的介电常数。提出了一个三态模型来描述tau的浓度依赖性。
The complex dielectric permittivity of aqueous sodium chloride solutions has been determined in the frequency range 0.2 less than or equal to v(GHz) less than or equal to 20 with a commercial dielectric measurement system based on a vector network analyzer. NaCl solutions 0.1 less than or equal to nz (mol kg(-1)) less than or equal to 5 (mass fraction 0.005 less than or equal to w less than or equal to 0.23) were investigated at 5, 20, 25, and 35 degrees C. An improved calibration procedure of the dielectric measurement system for conducting samples was developed, The complex permittivity spectra have been represented by a Cole-Cole relaxation time distribution. Where possible, the obtained fitting parameters, static permittivity epsilon and relaxation time tau, and distribution parameter cr, are compared with literature data to assess the performance of the instrument, which was found to be comparable to that of time domain and waveguide systems. Effective solvation numbers were deduced from the effect of NaCl concentration on epsilon. The data suggest that in addition to the irrotational bonding of water molecules by Na+ ions, kinetic depolarization under slip boundary conditions determines the solution permittivity. A three-state model is proposed to describe the concentration dependence of tau.