Dielectric relaxation phenomena and high frequency conductivity of rigid polar liquids in different solvents

Abstract

Abstract The double relaxation phenomena in apparently rigid aliphatic polar liquids (j) like chloral and ethyltrichloroacetate in nonpolar solvents (i) benzene, n-hexane and n-heptane under 4.2, 9.8 and 24.6 GHz electric fields at 30°C have been studied. Only five systems of polar-nonpolar liquid mixtures show the double relaxation times τ 1 and τ 2 due to rotation of their flexible parts and the whole molecules. The probability of showing the double relaxation phenomena is greater in aliphatic solvents at 9.8 and 24.6 GHz electric fields indicating their nonrigidity. This is also supported by the symmetric and asymmetric distribution parameters γ and δ estimated from values of x and y at w j → 0 involved with dimensionless dielectric constants k′ ij , k″ ij , k oij and k ∞ij of solutions. The variation of x and y with weight fractions w j 's of solutes are found to be unusual predicting their probable solute-solvent and solute-solute molecular association under high frequency (hf) electric fields. The dipole moments μ 1 and μ 2 of the flexible parts and the whole molecules from the slopes β's of hf conductivities σ ij ' s with w j 's and the estimated τ 1 and τ 2 reveal their solute-solute associations in the aliphatic solvents. The theoretical dipole moments μ theo 's in terms of available bond angles and bond moments conform the estimated μ j 's only to establish the existence of mesomeric, inductive and electromeric effects in them.