Acetone-water mixtures: Molecular dynamics using a semiempirical intermolecular potential

A theoretical study of some acetone -water solutions is per- formed considering a total number of molecules equal to 1000. A force field for the water-acetone interaction is presented. To this purpose we have considered four interaction centers on the acetone molecule and only one on the small water molecule. Then, the non electrostatic inter- molecular interaction between pairs of interaction centers placed on dif- ferent molecules has been modeled adopting Improved Lennard-Jones (ILJ) functions, which sum has been combined with the electrostatic interaction contribution (derived from the charge distributions on the molecules). The potential model has been used to perform some pre- liminary Molecular Dynamic simulations of the density at 298.15K of temperature and 1 atm of pressure for two different values of the ace- tone molar fractions, xacet = 0.745 and 0.986. The systems, formed by 1000 molecules, were previously thermalized at the selected temperature using the NVT ensemble. Production runs have been performed from the equilibrated systems using the NpT ensemble.