(500g) ms2: A Molecular Simulation Tool for Thermodynamic Properties

Due to the advances in available computing power, methodological efficiency and the development of accurate force fields, it is understood that ?molecular modeling and simulation will become a breakthrough technology that is widely accepted in the chemical industry and applied in conjunction with other predictive methods to meet the industry's evolving fluid property data needs? [1]. Efficient molecular simulations codes are needed for that purpose. Several highly developed MD simulation codes like AMBER and GROMACS are available that were developed with the focus on determining structural properties of solutions of biomolecules. The situation is less satisfactory for accurate molecular simulations of thermodynamic properties and in particular for phase equilibria, where presently few programs are publically available. In the present work the molecular simulation tool ms2 is presented, that was made publically available in 2010. The ms2 code was developed with the focus on efficient accurate simulations of thermodynamic properties of fluids including phase equilibria and transport properties for pure fluids and mixtures. The code is optimized for a fast execution on a broad range of computer architectures, spanning from single processor PCs over PC-clusters and vector machines to high end vector-parallel equipment. It is a standalone FORTRAN90 code that does not require any other software prerequisites and is provided as a source code. The code has successfully been used in many applications, among them several contributions to Industrial Fluid Property Simulation Challenges [2-4]. The most important features of ms2 will be presented as well as results from standard and advanced applications. Furthermore, results from benchmark tests with different codes will be discussed. [1] http://www.fluidproperties.org [2] F. Case, A. Chaka, D.G. Friend, D. Frurip, J. Golab, P. Gordon, R. Johnson, P. Kolar, J. Moore, R.D. Mountain, J. Olson, R. Ross, and M. Schiller. The second industrial fluid properties simulation challenge. Fluid Phase Equilib., 236(1-2):1?14, 2005. [3] F.H. Case, J. Brennan, A. Chaka, K. D. Dobbs, D.G. Friend, D. Frurip, P.A. Gordon, J. Moore, R.D. Mountain, J. Olson, R.B. Ross, M. Schiller, and V. K. Shen. The third industrial fluid properties simulation challenge. Fluid Phase Equilib., 260(2):153?163, 2007. [4] F. Case, J. Brennan, A. Chaka, K. Dobbs, D.G. Friend, P.A. Gordon, J. Moore, R.D. Mountain, J. Olson, R. Boss, M. Schiller, V.K. Shen, and E.A. Stahlberg. The fourth industrial properties simulation challenge. Fluid Phase Equilib., 274(1-2):2?9, 2008.