Molecular motions in simple liquids

Time-dependent correlation functions for simple liquids obtained by computer experiments are presented and interpreted in the framework of generalized hydrodynamics. Three main points are emphasized: (i) The self-motion is described in terms of a fraction coefficient non-local in time which presents a tail at large times; (ii) shear waves are present for wave vectors as low as 0.3 Å–1; (iii) Brillouin triplets seen in S(k,ω) are still present for values of the wave vector k as high as 0.3 Å–1.