Solid-solid transformations in a confined soft sphere fluid - art. no. 051507

Grand canonical Monte Carlo simulations are used to investigate the structu re of frozen phases in a confined soft sphere (Lennard-Jones) fluid for a b ulk state point lying close to the liquid-solid freezing line. The study re veals that the pore fluid not only freezes in the pore, but solid-solid tra nsformations occur in the two, and three-layered structures that form as th e pore height is varied. Using the in-plane bond angle order parameters and pair-correlation functions, the frozen structures and transformations are related to the variations in solvation force and pore density, Transformati ons from square to triangular lattices are observed in both the two- and th ree-layered regimes. In the three-layered regime, transformations occur fro m the body-centered tetragonal to hcp and fcc lattices as the pore height i s increased. During the transition from one to two layers, random buckled S tructures are observed. The structural transformations from square to trian gular lattices in the confined fluid also result in a splitting in the solv ation force curve.