The structure of fluid argon from high-pressure neutron diffraction and abinitio molecular dynamics simulations

The structure of supercritical argon at 350 K over a broad range of density (pressures between 5 to 90 MPa) is determined experimentally by high-press ure neutron diffraction, and theoretically from quantum chemically calculat ed ab initio pair potentials applied in molecular dynamics simulations. The origins of small discrepancies between theory and experiment are discussed . Together with previous results at 85 K in the liquid state, the overall a greement between theory and experiment, over a wide range of state points, is found to be quite good. This is remarkable, as no empirical parameters a re used for the calculations. (C) 1999 American Institute of Physics. [S002 1-9606(99)50630-2].