Investigation of the chemical potential by molecular dynamics simulation

The Widom test particle method is implemented in molecular dynamics simulations to investigate the chemical potential of various fluids. This method is found to be reliable and accurate at liquid density if a sufficient number of simulated particles are taken into account. In order to save computing time an importance sampling technique is used during the simulation. Moreover, it is shown that the size of the simulated system can generate spurious results. Finally, the role of the chemical potential as a test for the effective pair potentials is illustrated for one example: the liquid-vapour coexistence line of chlorine.