The structure of high-pressure adsorbed fluids in slit-pores

Abstract

We present simulation results for the packing for single center Lennard Jones models of adsorbed fluids such as methane, carbon dioxide and carbon tetrachloride at high pressure in carbon slit pores. These show a series of packing transitions that are well described by a lattice density functional theory model developed in our laboratory. By contrast, simulations show that these transitions are absent for a three-center model, which provides a more adequate representation of carbon dioxide. Analysis of the simulation results shows that alternations of flat lying molecules and rotated molecules can occur in this case as the pore width is increased. The presence or absence of quadrupoles has negligible effect on these high-density structures.