Solidlike phase transitions in a screened Wigner lattice. Statics

We generalize the concept of the Wigner lattice by assuming a system where the interaction between particles is proportional to r^-1 exp(-λr), where r is the interparticle distance and λ^-1 the Debye screening length. With Ewald's method we calculate the fractional energy difference between the static bcc and fcc structures. For λrₛ=1.05 we predict a phase transition, rₛ being the radius of the spherical volume of the unitary cell. Moreover, we compare our results with observations performed on polystyrene spheres in aqueous suspensions.