Dielectric relaxation of binary polar liquid mixture measured in benzene at 10 GHz frequency

Pramana

S Acharyya¹  S Sahoo²  K Dutta¹  S K Sit2¹ 

[1] Department of Physics, Dr. Meghnad Saha Institute of Technology, P.O. Debhog, Purba Medinipur 721 657, India$$;Department of Instrumentation Technology, Dr. Meghnad Saha Institute of Technology, P.O. Debhog, Purba Medinipur 721 657, India$$

关键词: Relaxation time;    hf conductivity;    dipole moment;    solute-solute interaction.;   

DOI  :  

学科分类：物理（综合）

来源: Indian Academy of Sciences

【 摘 要 】

The dielectric relaxation times 𝜏𝑗𝑘's and dipole moments 𝜇𝑗𝑘's of the binary (𝑗𝑘) polar liquid mixture of N,N-dimethyl acetamide (DMA) and acetone (Ac) dissolved in benzene (i) are estimated from the measured real 𝜎′𝑖𝑗𝑘 and imaginary 𝜎″𝑖𝑗𝑘 parts of complex high frequency conductivity 𝜎*𝑖𝑗𝑘 of the solution for different weight fractions 𝑤𝑗𝑘's of 0.0, 0.3, 0.5, 0.7 and 1.0 mole fractions 𝑥𝑗 of Ac and temperatures (25, 30, 35 and 40°C) respectively under 9.88 GHz electric field. 𝜏𝑗𝑘's are obtained from the ratio of slopes of 𝜎″𝑖𝑗𝑘 - 𝑤𝑗𝑘 and 𝜎′𝑖𝑗𝑘 - 𝑤𝑗𝑘 curves at 𝑤𝑗𝑘 → 0 as well as linear slope of 𝜎″𝑖𝑗𝑘 - 𝜎′𝑖𝑗𝑘 curves of the existing method (Murthy et al, 1989) in order to eliminate polar-polar interaction in the latter case. The calculated 𝜏's are in excellent agreement with the reported 𝜏's due to Gopalakrishna's method. 𝜇𝑗𝑘's are also estimated from slopes 𝛽's of total conductivity 𝜎𝑖𝑗𝑘 -𝑤𝑗𝑘 curves at 𝑤𝑗𝑘 → 0 and the values agree well with the reported 𝜇's from G.K. method. The variation of 𝜏𝑗𝑘's and 𝜇𝑗𝑘's with 𝑥𝑗 of Ac reveals that solute-solute molecular association occurs within 0.0-0.3𝑥𝑗 of Ac beyond which solute-solvent molecular association is predicted. The theoretical dipole moments 𝜇theo's are calculated from bond angles and bond moments to have exact 𝜇's only to show the presence of inductive, mesomeric and electromeric effects in the substituent polar groups. The thermodynamic energy parameters are estimated from ln (𝜏𝑗𝑘𝑇) against 1/𝑇 linear curve from Eyring's rate theory to know the molecular dynamics of the system and to establish the fact that the mixture obeys the Debye-Smyth relaxation mechanism.

【 授权许可】

Unknown