Temperature-dependent dielectric relaxation study of chlorobenzene with n-methylformamide from 10 MHz to 20 GHz

The complex permittivity spectra of chlorobenzene with n-methylformamide were determined in the frequency range of 10 MHz to 20 GHz using time domain reflectometry (TDR) in the temperature range 15 degrees C to 45 degrees C for 11 different concentrations of the system. The dielectric parameters viz. static dielectric constant (epsilon(0)) and relaxation time (T) have been obtained by the least squares fit method. Excess properties and Kirkwood correlation factor of the mixtures have been determined. For the temperature range, considered here, the permittivity and relaxation time increased with the percentage of n-methylformamide. The excess permittivity is found to be negative in the chlorobenzene-rich region and positive in the n-methylformamide-rich region. However the excess inverse relaxation time has the reverse trend. The static dielectric constants for the mixtures have been fitted with the modified Bruggeman model. (c) 2005 Elsevier B.V All rights reserved.