Hiester Thorsten, Dietrich S, Mecke Klaus
Institut für Theoretische Physik, Universität Erlangen-Nürnberg, Staudtstrase 7, D-91058 Erlangen, Germany.
J Chem Phys. 2006 Nov 14;125(18):184701. doi: 10.1063/1.2358341.
Thermally excited capillary waves at fluid interfaces in binary liquid mixtures exhibit simultaneously both density and composition fluctuations. Based on a density functional theory for inhomogeneous binary liquid mixtures we derive an effective wavelength dependent Hamiltonian for fluid interfaces in these systems beyond the standard capillary-wave model. Explicit expressions are obtained for the surface tension, the bending rigidities, and the coupling constants of compositional capillary waves in terms of the profiles of the two number densities characterizing the mixture. These results lead to predictions for grazing-incidence x-ray scattering experiments at such interfaces.
二元液体混合物中流体界面处的热激发毛细波同时表现出密度和成分涨落。基于非均匀二元液体混合物的密度泛函理论，我们推导出了这些系统中流体界面超出标准毛细波模型的有效波长相关哈密顿量。根据表征混合物的两种数密度分布，得到了表面张力、弯曲刚度和成分毛细波耦合常数的显式表达式。这些结果为这类界面的掠入射x射线散射实验提供了预测。
