Rotational and translational diffusion in glass-forming N,N,-diethyl-3-methylbenzamide (DEET)

Rotational and translational diffusion in N,N,-diethyl-3-Methylbenzamide (DEET) are investigated in wide frequency and temperature ranges by a combination of broadband dielectric spectroscopy (BDS), pulsed field gradient nuclear magnetic resonance (PFG NMR), dynamic mechanical spectroscopy (DMS) and calorimetry. It is proven that the (dynamic) glass transition (as measured by BDS, DMS and calorimetry) and charge transport (as measured by PFG NMR and BDS) follow quantitatively the Einstein and Einstein-Smoluchowski relations. The effective number densities of molecules participating in rotational and translational diffusion are found to coincide within the limits of experimental accuracy. Rotational Brownian fluctuations corresponding to the dynamic glass transition result in translational diffusion of DEET molecules.