On the solid-like phase transition in crystals of polystyrene spheres in aqueous suspensions

We present results of calculations for the fractional energy difference between the bcc and fcc phases present in ordered systems of polystyrene spheres in aqueous suspensions. The theoretical model developed for those systems is an extension of the concept of a Wigner lattice. The interaction between the particles is assumed to be a screened coulomb potential. We conclude that the phase transition occurs when λr₅ = 1.05 where λ^-1 is the Debye screening length and r_s is the radius of the spherical volume of the unitary cell.