THE P,T-DEPENDENCE OF SELF-DIFFUSION IN FLUID AMMONIA

Self-diffusion coefficients D for fluid NH3 have been obtained at high pressures by the NMR pulsed field gradient method for the first time between the melting pressure curve and 473 K lit pressures up to 200 M Pa. Compared to H2O and the lower alcohols D of NH3 shows a surprising ly weak T dependence. The data are analyzed in the rough-hard-sphere ( RHS) model. The A-parameter of this model gives no indication for the influence of hydrogen bonding upon the translational dynamics in NH3.