On the Ginzburg temperature of ionic and dipolar fluids
On the Ginzburg temperature of ionic and dipolar fluids
复制标题
关于离子和偶极流体的金兹堡温度
DOI：
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发表时间：
1997
期刊：
影响因子：
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通讯作者：
W. Schröer
中科院分区：
文献类型：
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作者：
V. Weiss;W. Schröer
在广义货车德瓦尔斯理论的框架内研究了流体中的临界涨落。平方梯度项-添加到亥姆霍兹自由能密度的朗道展开-是按照类似于最初由货车德瓦尔斯在表面张力理论中提出的程序获得的，但是用近似的对分布函数代替最初使用的Heaviside阶梯函数。代表离子流体，我们选择的限制原始模型（RPM），并处理它内的德拜-休克尔理论，从而忽略了离子配对的影响。另一个近似的极端-完整的离子配对导致的硬偶极哑铃流体-是模仿偶极硬球（DHS）组成的流体。对于这种情况，我们使用Onsager反应场和第二压力维里系数。我们计算了关联长度和金兹伯格温度的振幅，发现（在减少的数量）Δ Tgi *=3.50和ΔTGi*=0.0087的离子系统，一个...
Critical fluctuations in fluids are investigated within the framework of the generalized van der Waals theory. The square-gradient term—added to the Landau expansion of the Helmholtz free energy density—is obtained following a procedure similar to that originally proposed by van der Waals in the theory of surface tension, however replacing the Heaviside step function originally used by an approximative pair distribution function. Representative for ionic fluids we choose the restricted primitive model (RPM) and treat it within the Debye–Huckel theory, thus neglecting effects of ion pairing. The other approximative extreme—complete ion pairing resulting in a fluid of hard dipolar dumbbells—is mimicked by a fluid composed of dipolar hard spheres (DHS). For this case we use the Onsager reaction field and the second pressure virial coefficient. We calculate the amplitudes of the correlation length and the Ginzburg temperatures, and find (in reduced quantities) ξ0*=3.50 and ΔTGi*=0.0087 for the ionic system, a...