A simple effective pair potential for the molecular simulation of the thermodynamic properties of ammonia

A new optimized effective pair potential model is proposed, which is approp riate for the prediction of thermodynamic properties of fluid ammonia inclu ding vapour-liquid coexistence data. The phase behaviour is determined usin g a recently developed version of the Gibbs ensemble Monte Carlo method. Fu rthermore, liquid structure characteristics, the dielectric constant and su percritical properties are determined by Monte Carlo simulations in the iso thermal-isobaric ensemble. The second virial coefficient of the pair potent ial model is calculated over a broad range of temperature. All properties a re compared with experimental data or results of a multi-parameter equation of state for ammonia. The new model is found to yield coexistence properti es and second virial coefficients in good agreement with experimental data and the results of the equation of state, respectively.