Entropic Identification of the First Order Freezing Transition of a Suspension of Hard Sphere Particles

We analyze the experimental particle current autocorrelation function of suspensions of hard spheres. Interactions between the particles are mediated by thermally activated acoustic excitations in the solvent. Those acoustic modes are tantamount to the system’s (energy) microstates and by their orthogonality, each of those modes can be identified with an independent Brownian particle current. Accordingly, partitioning of the system’s energy states is impressed on the current autocorrelation function. This impression provides a novel measure of the entropy and location of a partitioning or entropy limit at a packing fraction that coincides with that of the observed suspension’s first order freezing transition.