An analytical equation of state for ammonia at high temperatures and high pressures

An analytical equation of state is presented for ammonia to describe its thermodynamic properties over wide ranges of temperatures and pressures up to 3000 K and 20 GPa, respectively. The equation of state contains well-defined parameters, two of which have been slightly adjusted around their global values based on a limited set of experimental data. The properties of ammonia predicted by the new equation of state are in very good agreement with the experimental data and the first-principles molecular dynamics simulation results over a broad range of temperatures and pressures. The new equation of state is expected to supplement molecular simulations at conditions where experimental data are not yet available.