VACANCY CALCULATION OF VISCOSITY OF POTASSIUM -AMMONIA SOLUTIONS

The theory of random flights and the Stokes-Einstein expression for translational diffusion are combined to calculate the viscosity of a liquid. The viscosity is inversely proportional to pν, the probability of a molecular vacancy. pν is evaluated from a quasilattice model for salt solutions as well as alkali-metal solutions in liquid ammonia and the contribution to the viscosity η which varies linearly with concentration M is calculated. The calculated values of η0-1(dη/ dM)0| of salt solutions are 20%-35% larger than the observed values. Calculated values of | η0-1 (dη/dM)0 | for alkali-metal solutions are somewhat larger than the observed values but the coefficients have the correct sign and temperature dependence.