A FORCE-FIELD FOR LIQUID DIMETHYL-SULFOXIDE AND PHYSICAL-PROPERTIES OF LIQUID DIMETHYL-SULFOXIDE CALCULATED USING MOLECULAR-DYNAMICS SIMULATION

A computational model of dimethyl sulfoxide (DMSO) is presented. The model is rigid and uses a pairwise additive potential energy function. It is based on parameters of existing models and the GROMOS force field. In trial molecular dynamics simulations the parameters were optimized with respect to the experimental density, the heat of vaporization, and the self-diffusion coefficient of liquid DMSO. Simulations using the final model reproduced these properties. It is important for a reliable model to be able to reproduce experimental data not used in the parameterizing procedure. Other physical properties of liquid DMSO, including rotational correlation time, thermal expansion coefficient, isothermal compressibility, specific heat, excess Helmholtz free energy, static dielectric permittivity, and shear viscosity have also been calculated from molecular dynamics simulations using the model. The results are in good agreement with experiment. However, the comparison with experimental data also suggests that the model slightly overestimates the mobility of DMSO molecules in the Liquid.