The first careful experimental studies of gas-liquid phase separation (capillary condensation) in well characterized materials, giving the full gas-liquid phase diagram and critical point for a range of confined systems, were recently reported by Thommes and Findenegg. In this project, the PIs will use Grand Canonical Monte Carlo simulation to study these phase changes in controlled pore glasses (CPGs), with a view to understanding and interpreting the confinement effects involved. The simulations will employ an efficient parallelized Monte Carlo program, based on histogram methods, and using the SemiGrand Ensemble. Models of CPG will be prepared by two different methods involving the use of Quench Molecular Dynamics to quench supercritical silica. These methods will be tested and the best will be used in the future work. The absorption, and phase transitions for sulfur hexafluoride in CPGs of various pore diameters will be calculated and compared with the experimental data. This work will be followed by studies of melting and freezing of simple fluids in CPGs, and again comparisons with experiment will be an important part of the project.
