| Popis: |
Structural and dynamical properties of heterocyclic organic compound Isatin in the solution state with DMSO has been studied in the frequency region of 10 MHz to 50 GHz over the temperature range of 273.15 K-298.15 K with the help of Time domain Reflectometry. Some of the dielectric parameters like relaxation time (τi), static dielectric constant (εi), dipole moment (𝜇̂) , correlation factor (gi), number of irrotationaly bound DMSO molecule (Zib) and effective volume of rotation (Veff) has been evaluated and expressed in terms of molecular interaction and hydrogen bonding. Beside these thermodynamic parameters such as molar entropy of activation (Δ𝑆𝜏𝑖), molar enthalpy of activation (Δ𝐻𝜏𝑖), molar free energy of activation ( Δ𝐹𝜏𝑖 ) has also been calculated. The dielectric permittivity spectra and relaxation behaviour of Isatin at different DMSO concentrations was analyzed using Cole-Davidson model. Two relaxation peaks i.e. high frequency relaxation and low frequency relaxation has been observed for Isatin+DMSO. The low frequency relaxation peak observed in the range of about 4-5 GHz is attributed to the rotation of Isatin molecule while high frequency relaxation peak observed in the range of about 18-21 GHz is attributed to the reorientation of DMSO molecule. With increasing isatin concentration dielectric loss peaks shifted towards lower frequency side at all the studied temperature and concentrations. Dielectric constant was found to be increasing with increasing concentrations except at 0.2265M. For all the studied temperatures dielectric constant was found to be decreasing with temperature. Dipole moment calculated using Cavell’s equation was found to be decreasing with increasing concentrations, 𝜇̂ was found to be increasing towards lower temperature, whereas, the variation in the magnitude is very small towards higher concentration. |
