DIELECTRIC-RELAXATION OF H2O/D2O MIXTURES

Between 1 MHz and 55 GHz the complex dielectric spectrum has been measured at 25-degrees-C for D2O and for H2O/D2O mixtures with mole fraction x=0.25, 0.5 and 0.75 of D2O. A Debye-type relaxation spectral function has been fitted to the frequency-dependent data to yield the static permittivity, the extrapolated high-frequency permittivity, and the dielectric relaxation time. These data are compared to those for H2O. Contrary to what is expected on grounds of recent measurements of the specific electric conductivity, the dependence of the relaxation time upon the mole fraction of D2O is a linear function.