Fluids undergoing phase separation exhibit complicated domain patterns. In this study we perform molecular-dynamics simulations for two- and three-dimensional Lennard-Jones fluids in order to investigate the relationship between statistical properties of domain structure and system temperature. The asymptotic form factor of each pattern is obtained using scaling and its temperature dependence studied. In particular the asymptotic tail of the form factor is analyzed. This tail is related to the domain-wall structure. At low system, temperatures, the form factor satisfies Porod’s law; its asymptotic tail decreases as S(k)∼${\mathit{k}}^{\mathrm{-}(\mathit{D}+1)}$ where D is the system dimensionality. However, it is found that the decay of the asymptotic tail becomes slower than that of the Porod tail at higher temperatures in both the two- and three-dimensional systems. This indicates that the dimension of the domain wall is fractal and increases with increasing system temperature.

• Received 17 October 1994

DOI:https://doi.org/10.1103/PhysRevB.51.2715