(113h) A New Method to Obtain Chemical Potential Differences in Periodic Molecular Simulations

Authors: 
Moore, S. G., Brigham Young University
Wheeler, D. R., Brigham Young University


The chemical potential is a very useful and important property. It can be related to many different phenomena such as phase equilibria, including solubility and osmosis; transport processes such as diffusion; as well as chemical reaction rates. These phenomena are important in many industrial applications. A new method of simulating differences in chemical potentials using molecular simulations has been developed for single-component and multi-component systems. This method uses a periodic external force-field to produce a density or concentration gradient across the simulation cell. The difference in the chemical potential across the system can then be directly related to the applied field. In contrast to methods such as Widom's or Gibbs Ensemble Monte Carlo, no difficult particle insertions are necessary, so the method is well-suited for large, structured molecules and for dense liquids. We will report a few sample calculations for systems of Lennard-Jones fluids, solids, and binary mixtures.