title: Microwave dielectric relaxation spectroscopy study of propylene glycol/ethanol binary mixtures: Temperature dependence.
abstract: Complex dielectric permittivity measurements of propylene glycol (PG) in ethanol at various mole fractions were measured by using open-ended coaxial probe technique at different temperatures in the frequency range 0.02<ν/GHz<20. The dipole moment (μ), excess dipole moment (Δμ),excess permittivity (εE), excess inverse relaxation time(1/τ)E, Bruggeman parameter (fB), excess Helmholtz energy (ΔFE) are determined using experimental data. From the minimum energy based geometry optimization, dipole moments of individual monomers of propylene glycol and ethanol and their binary system have been evaluated theoretically at gaseous state as well as alcoholic medium by using PCM and IEFPCM solvation models from the Hatree-Fock (HF) and Density Functional Theory (DFT-B3LYP) methods with 6-311G* and 6-311G** basis sets. The obtained results have been interpreted in terms of the short and long range ordering of the dipoles, Kirkwood correlation factor (geff), thermodynamic parameters, mean molecular polarizability (αM) and interaction in the mixture through hydrogen bonding.
authors.affiliation: Department of Physics, School of Technology, Gitam University - Hyderabad, Rudraram Village, Patancheru (Mandal) 502329, India.
authors.forename: T
authors.initials: T
authors.lastname: Vishwam
authors.affiliation: Department of Physics, Acharya Nagarjuna University, Nagarjunanagar, 522510, India.
authors.forename: Suriya
authors.initials: S
authors.lastname: Shihab
authors.affiliation: Department of Physics, Indian Institute of Technology Madras, Chennai 600036, India.
authors.forename: V R K
authors.initials: VRK
authors.lastname: Murthy
authors.affiliation: Department of Chemical Science, Faculty of Science, Universiti Tunku Abdul Rahman, Jalan Universiti, Bandar Barat, 31900 Kampar, Perak, Malaysia.
authors.forename: Ha Sie
authors.initials: HS
authors.lastname: Tiong
authors.affiliation: Department of Physics, Acharya Nagarjuna University, Nagarjunanagar, 522510, India. Electronic address: sreeharisastry@yahoo.com.
authors.forename: S
authors.initials: S
authors.lastname: Sreehari Sastry
keywords: Complex permittivity; Dielectric relaxation; Excess dielectric parameters; Helmholtz energy and mean molecular polarizability (α(M))