RESOLVING THE STRUCTURAL RELAXATION OF A 2-DIMENSIONAL LIQUID USING APERTURED CROSS-CORRELATION FUNCTIONS

Time-delayed intensity cross correlation functions are used to analyze the structural relaxation of a two-dimensional liquid of soft disks a s simulated using a molecular dynamics algorithm. The structural relax ation exhibits an increasing long time tail as the freezing transition is approached. A cross correlation function designed to select out on ly local hexagonal fluctuations is used to demonstrate explicitly that this slow relaxation arises from crystalline fluctuations. A theoreti cal treatment of the role of aperture size and cluster distribution in the scattering correlation functions is presented. (C) 1997 American Institute of Physics. [S0021-9606(97)51444-9].