From molecular-dynamics simulation of liquid-liquid interface at low temperatures between two simple liquids, we determine two point correlation functions, also for the liquid-vacuum interface. True Fourier vector in-plane dependence, correlations parallel and perpendicular to the interface, susceptibilities, and surface scattering factor (in the Born approximation) are discussed. The Bhatia-Thornton transformation is generalized to inhomogeneous systems and applied. Effects of capillary waves, surface reconstruction, surface layering, and prominence of bulk structures are found and discussed.