Gas–liquid interactions in solution*

Two approaches are followed to understand how molecular interactions influence the macroscopic properties of solutions: (1) experiment, through the determination of gas solubility, and (2) computer simulation, used to evaluate microscopic properties (structural and energetic). Examples of application of these approaches are considered in order to explain the properties of solutions containing fluorinated fluids or ionic liquids. The molecular structures and interactions are described by force fields built from ab initio quantum chemical calculations. These models allow the determination of free energies from computer simulations by using appropriate energy routes provided by statistical mechanics. The macroscopic properties related to the process of dissolution of several gases are interpreted in terms of the molecular structure of the solutions and of the solute–solvent interactions.