K. Dutta et al., Dielectric relaxation phenomena and high frequency conductivity of rigid polar liquids in different solvents., J MOL LIQ, 88(2-3), 2000, pp. 229-241
The double relaxation phenomena in apparently rigid aliphatic polar liquids
(j) like chloral and ethyltrichloroacetate in nonpolar solvents (i) benzen
e, n-hexane and n-heptane under 4.2, 9.8 and 24.6 GHz electric fields at 30
degreesC have been studied. Only five systems of polar-nonpolar liquid mix
tures show the double relaxation times tau (1) and tau (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 an
d 24.6 GHz electric fields indicating their nonrigidity. This is also suppo
rted by the symmetric and asymmetric distribution parameters gamma and delt
a estimated From values of x and y at w(j) --> 0 involved with dimensionles
s dielectric constants k(ij)' k(ij)", k(oij) and k(ooij) of solutions. The
variation of x and y with weight fractions w(j)'s of solutes are found to b
e unusual predicting their probable solute-solvent and solute-solute molecu
lar association under high frequency (hf) electric fields. The dipole momen
ts mu (1) and mu (2) of the flexible parts and the whole molecules from the
slopes beta 's of hf conductivities sigma (ij)'s with w(j)'s and the estim
ated tau (1) and tau (2) reveal their solute-solute associations in the ali
phatic solvents. The theoretical dipole moments mu (theo)'s in terms of ava
ilable bond angles and bond moments conform the estimated mu (j)'s only to
establish the existence of mesomeric, inductive and electromeric effects in
them. (C) 2000 Elsevier Science B.V. All rights reserved.