Figure 3:

Concentration dependence of deviation from pure water (W) values of Arrhenius model fit diffusion parameters (collision frequency, A, and activation energy, E_a) is shown in (a) for 0% to 40% PVP. The vertical axis in (a) is common for difference in activation energies and ratio of collision frequencies relative to pure water. Measured ADC_PVP normalized to the theoretical diffusion value of pure water, D_W (calculated from Speedy-Angell relation) is shown in (b) for 0% to 50% PVP and three temperatures color-coded in the legend. Dashed curves show the linear (in a) and quadratic (in b) least squares fit for %PVP dependence over plotted ranges. The fit intercepts were constrained to 1 (for normalized A and ADC) and 0 (for E_a difference), and the fit slopes are listed on the figures.