Thermodynamic and structural properties were determined by Monte Carlo simulations in isothermal-isobaric system. We were interested in pure ammonia-water and methanol-water mixtures and also in solvation of nonpolar solute in infinite dilution of ammonia-water and methanol-water mixtures. We used two-dimensional Mercedes-Benz type of model. Water and ammonia model can be similarly described. They are both represented as a Lennard-Jones disk with hydrogen bonding arms, but differ in the number of those arms. MB methanol model is represented as a Lennard-Jones disk with two hydrogen bonding arms as a hydroxyl group and one additional disk as a methyl group.
When calculating thermodynamic properties, we determined how the density, the thermal expansion coefficient, the isothermal compressibility and the heat capacity at constant pressure change with increasing temperature and fraction of ammonia or methanol in the corresponding mixture. Then we have drawn snapshots of studied systems, radial distribution functions and have made an analysis of hydrogen bonding and an analysis of formed clusters.
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