Mecke K R, Dietrich S
Fachbereich Physik, Bergische Universität Wuppertal, D-42097 Wuppertal, Federal Republic of Germany.
Phys Rev E Stat Phys Plasmas Fluids Relat Interdiscip Topics. 1999 Jun;59(6):6766-84. doi: 10.1103/physreve.59.6766.
Starting from a density functional theory for inhomogeneous fluids we derive an effective Hamiltonian for liquid-vapor interfaces of simple fluids which goes beyond the common phenomenological capillary-wave description. In contrast to other approaches we take into account the long-ranged power-law decay of the dispersion forces between the fluid particles which changes the functional form of the wave-vector-dependent surface tension qualitatively. In particular, we find two different forms of the bending rigidity for the capillary waves, a negative one for small wave vectors determined by the long-ranged dispersion forces and a positive rigidity for large wave vectors due to the distortions of the intrinsic density profile in the vicinity of the locally curved interface. The differences to the standard capillary-wave theory and the relevance of these results for the interpretation of scattering experiments are discussed.
从非均匀流体的密度泛函理论出发，我们推导了简单流体液 - 气界面的有效哈密顿量，它超越了常见的唯象毛细波描述。与其他方法不同，我们考虑了流体粒子间色散力的长程幂律衰减，这定性地改变了波矢依赖的表面张力的函数形式。特别地，我们发现毛细波的弯曲刚度有两种不同形式，一种是由长程色散力决定的小波矢下的负刚度，另一种是由于局部弯曲界面附近本征密度分布的畸变导致的大波矢下的正刚度。讨论了与标准毛细波理论的差异以及这些结果对散射实验解释的相关性。
