RISM study of sulphur dioxide at the liquid-vapour coexistence line

Abstract

Sulphur dioxide is studied by the reference interaction site model. The site-site potential was modelled by the Lennard-Jones potential functions and direct correlation functions were calculated for thermodynamic points close to the liquid-vapour coexistence line. By means of the correlation functions the pressure and mean potential energy have been calculated. The results were compared with molecular dynamics results and also with experimental data. It turned out that the RISM procedure is competitive with the molecular dynamics method only in a relatively narrow temperature range close to the midpoint between the triple point and the critical point. There the agreement between RISM and molecular dynamics method is quite encouraging and also the experimental values of pressure and mean potential energy and compressibility are satisfactorily reproduced. On either side of this region RISM does not reproduce properly the structure and energetics of the liquid SO 2 system.