Dielectric relaxation of para polar liquids under high frequency electric field

Abstract The structural and associational aspects of nonspherical para polar liquids (j) in nonpolar solvents (i) are studied through high frequency conductivities σ ij 's of solutions. The relaxation time τ of the respective liquids under 3cm. wavelength electric field at various experimental temperatures in °C are estimated from the slope of individual variations of real σ ′ ij and imaginary σ ″ ij parts of hf complex conductivity σ ∗ ij with weight fractions w j 's of polar liquid. The temperature variation of τ for comparatively larger nonspherical para molecules in dioxane are not strictly obeyed by the Debye model unlike other simpler para di- or tri-substituted benzene in benzene. Thermodynamic energy parameters ΔH τ , ΔS τ and ΔF τ are obtained from Eyring's rate process equation with the estimated τ's in order to get information on the solvent environment around them. The higher values of γ obtained from lnτ j T against lnη equation indicate the solid phase rotators for the liquids. The estimated Kalman and Debye factors τ j T/η γ and τ j T/η establish the Debye relaxation mechanism for almost all the para-molecules. The obtained dipole moments μ j 's in terms of slope β of σ ij -w j curve and dimensionless parameter ‘b’ involved with estimated τ are then compared with the reported μ and μ theo obtained from bond angles and bond moments. The μ j 's of para liquids are often zero but at other temperatures they show net moments. The slight disagreement between the measured and theoretical μ's reveals the presence of the inductive and mesomeric moments of substituted polar groups in molecules at different temperatures.