Pressure effects on diffusion in liquid ammonia : A simulation study using a combination of isobaric-isothermal and microcanonical molecular dynamics

The effects of pressure on translational and rotational diffusion in liquid ammonia are investigated by means of molecular dynamics simulations. Calculations are done at two different temperatures and at many different pressures by using a two-part protocol involving molecular dynamics in isobaric-isothermal ensemble in the first part and in microcanonical ensemble in the second part. Our results are analyzed in terms of pressure-induced changes in structural properties such as packing and hydrogen bond properties. Also, the present results of liquid ammonia are compared with corresponding results for other hydrogen bonded liquids that were reported in recent years.