Collective dynamics in quasibidimensional colloidal suspensions

We report the direct measurement by video microscopy of the Van Hove function of quasi-two-dimensional colloidal suspensions. Under these conditions of confinement, the effective interparticle potential exhibits an intermediate range attractive component. This is obtained by deconvoluting the measured pair correlation function using an inverse Monte Carlo method. The experimental dynamic behavior is well represented by a Brownian dynamics simulation, performed using the experimental pair potential and an effective quasi-two-dimensional short-time diffusion coefficient. [S0031-9007(98)06595-8].