“Umbrella samplmg” has been incorporated in the thermodynamic integration method to obtain a potential of mean force by slow growth molecular-dynamics simulations. The method was tested for liquid argon, for which good agreement was obtained with a standard potential of mean force, as derived from the radial pair-correlation function. For a sodium chloride ion-pair in aqueous solution the calcu...

The aim of thermodynamic integration is to compute the difference in a thermodynamic property (usually the free energy) of the system between some reference state and the state of interest. To measure the free energy change from initial to final state, thermodynamic parameters characterizing the system are changed infinitely slowly so that at each stage along the path the system is in equilibri...