Linewidth and viscosity of isobutyric acid—deuterium oxide mixtures of critical composition above and below the phase separation temperature

Linewidth and visocity measurement covering the single phase and two phase region were made. Comparison of the data with the mode–mode coupling results of Kawasaki show good agreement with no adjustable parameters. In the one phase region measurements of autocorrelation functions indicate small deviations from a single exponential when ‖T −Tc‖?0.05 °C. The shear viscosity exponent φ was found to be 0.077±0.002, somewhat larger than the theoretical estimates.