Methods to Compute Pressure and Wall Tension in Fluids containing Hard Particles

Abstract

Colloidal systems are often modelled as fluids of hard particles (possibly with an additional soft attraction, e.g. caused by polymers also contained in the suspension). in simulations of such systems, the virial theorem cannot be straightforwardly applied to obtain the components of the pressure tensor. In systems confined by walls, it is hence also not straightforward to extract the excess energy due to the wall (the "wall tension") from the pressure tensor anisotropy. A comparative evaluation of several methods to circumvent this problem is presented, using as examples fluids of hard spheres and the Asakura-Oosawa model of colloid-polymer mixtures with a size ratio $q=0.15$ (for which the effect of the polymers can be integrated out to yield an effective attractive potential between the colloids). Factors limiting the accuracy of the various methods are carefully discussed, and controlling these factors very good mutual agreement between the various methods is found.

15 pages, 6 figures

Cited by in corpus (7)

• Logarithmic Finite-Size Effects on Interfacial Free Energies: Phenomenological Theory and Monte Carlo Studies
• Determination of the origin and magnitude of logarithmic finite-size effects on interfacial tension: Role of interfacial fluctuations and domain breathing
• Crystal nuclei in melts: A Monte Carlo simulation of a model for attractive colloids
• Simulation of fluid-solid coexistence in finite volumes: A method to study the properties of wall-attached crystalline nuclei
• Wall-liquid and wall-crystal interfacial free energies via thermodynamic integration: A molecular dynamics simulation study
• Lennard-Jones systems near solid walls: Computing interfacial free energies from molecular simulation methods
• Computation of the solid-liquid interfacial free energy in hard spheres by means of thermodynamic integration