Dielectric relaxation in dipolar liquids: Route to Debye behavior via translational diffusion

A microscopic theory for the long-wavelength dielectric dispersion [ε(ω)] in a strongly correlated dipolar liquid is presented. The calculated ε(ω) is stongly non-Debye if only the orientational mechanism of polarization relaxation is considered. However, simple Debye behavior is recovered when the translational contribution to polarization relaxation is significant. In addition, the present theory explains the computer simulation results of Pollock and Alder satisfactorily.