Pressure Dependence of Self-Diffusion in Fluid NH_3 and ND_3
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Self-diffusion coefficients D for fluid NH<SUB>3</SUB> and ND<SUB>3</SUB> have been obtained at high pressures by the NMR pulsed field gradient method for the first time between the melting pressure curve and 473K at pressures up to 200 MPa. The ratio [D (NH<SUB>3</SUB>) /D (ND<SUB>3</SUB>) ]T, p defines the dynamic isotope effect. It has a very small p-dependence and a significant Tdependence. Compared to H<SUB>2</SUB>O and the lower alcohols D of ammonia shows a surprisingly weak p and T dependence. The data are analysed 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 fluid ammonia.
- The Review of High Pressure Science and Technology
The Review of High Pressure Science and Technology 7, 1432-1434, 1998
The Japan Society of High Pressure Science and Technology