We have used a density-functional theory based on the interaction site model to predict the liquid-vapor coexistence curve of nitrogen fluid. The pressure and chemical potential were calculated from thermodynamic integrations. The different paths of thermodynamic integration provide slightly different predictions for the liquid-vapor coexistence curve. However, these critical points and coexistence curves evaluated by the theory are in qualitative agreement with the experimental data. The theoretical coexistence curves scaled to critical constants agree with the experimental data quantitatively.
Department of Knowledge-based Information Engineering, Toyohashi University of Technology, Tempaku-cho, Toyohashi, 441-8580 Japan. sumi@cochem2@tutkie.tut.ac.jp
