Studies of porosity and diffusion coefficient in porous matrices by computer simulations

The Structural Properties and Diffusion of a Three-Dimensional Isotropic Core-Softened Model Fluid in Disordered Porous Media. Molecular Dynamics Simulation

The microscopic structure and dynamic properties of an isotropic three-dimensional core-softened model fluid in disordered matrices of Lennard-Jones particles have been studied. Molecular dynamics computer simulations in Grand Canonical ensemble were used as the methodological tools. It was shown that the microscopic structure of the fluid is characterized by anomalies similar to those found in a bulk model, but that it is affected by the fluid-matrix interactions. The dynamic properties also exhibit anomalous dependence on fluid density, but the magnitude of these anomalies is suppressed in comparison to the bulk fluid model. The anomalous behaviour of the diffusion coefficient is attributed to structural changes in the first coordination shell of a given fluid particle. It seems that the anomalies can only be suppressed at matrix densities which are higher than those studied in the present work.