Hard convex body fluids in random porous media: Scaled particle theory

The scaled particle theory (SPT) is applied to describe thermodynamic properties of hard convex body (HCB) fluid in random porous media. To this purpose we extended the SPT2 approach, which has been developed previously for a hard sphere fluid in random porous matrices. The analytical expressions for the chemical potential and the pressure of an HCB fluid in an HCB or an overlapping hard convex body (OHCB) matrix are obtained and analyzed. Within the SPT2 approach a series of new approximations are proposed. The grand canonical Monte Carlo (GCMC) simulations are performed to verify an accuracy of the SPT2 and the developed approaches. The obtained analytical expressions include three types of porosity: the geometrical porosity ϕ0, the probe particle porosity ϕ and the porosity ϕ⁎ defined by the maximum packing fraction of a fluid in a given matrix. The effect of nonsphericity parameters of matrix and fluid particles on the thermodynamic properties of a fluid is discussed.