THE CHEMICAL-POTENTIAL IN ATOMICALLY INHOMOGENEOUS FLUIDS IN EXTERNALFORCE-FIELDS BY COMPUTER-SIMULATION

The accuracy and practicality of the Widom fictitious-particle inserti on method for determining the chemical potential is tested for very in homogeneous fluids in strong external potentials by a series of molecu lar dynamics computer simulations. The chemical potential determined i n this way is found, as predicted, on an atomic scale to be independen t of position in the fluid to a few percent even when the density vari es by up to a factor 80. This severe test means that this method of de termining chemical potential is established as reliable and accurate i n any well-found computer simulation even when the system is very inho mogeneous.