(433d) Closure-Based Classical Density Functional Theory: A Novel Approach to Study Fluid-Solid Phase Transitions in Atomistic and Colloidal Systems

Fluid-solid phase transitions in colloidal systems with long and short range interparticle interactions are important in various modern fabrication processes with applications in supercomputing, characterization of proteins and nano/micro devices. We explore classical density functional theory (DFT) as a tool for making predictions of freezing transitions in colloids. Specifically we develop a novel DFT formulation that employs a closure relation in the form of a bridge functional to sum the higher order terms in the free energy expansion. The bridge functional for freezing transitions is qualitatively and quantitatively different from conventional closures like hypernetted-chain and Percus-Yevick, which are known to give good results in inhomogeneous liquid states. In previous work we have developed a highly accurate representation of the bridge functional for the hard sphere potential. Here we explore its form for commonly employed atomistic and colloidal potentials, such as inverse power repulsions and depletion attraction. Initial results suggest that there is some universality of the bridge functional across repulsive potentials of different types, which is promising for the development of widely applicable closures.