Molecular dynamics of iso-amyl bromide by dielectric spectroscopy, and the effects of a nonpolar solvent, 2-methylpentane, on the spectral features
Citation:
O. E. Kalinovskaya and J. K. Vij, Molecular dynamics of iso-amyl bromide by dielectric spectroscopy, and the effects of a nonpolar solvent, 2-methylpentane, on the spectral features, Journal of Chemical Physics, 111, 24, 1999, 10979 - 10985Download Item:
Abstract:
To gain insight into the effects of the weakening of the electrostatic interactions on molecular
dynamics when polar molecules are dissolved in a nonpolar solvent, the dielectric polarization and
relaxation behaviors of iso-amylbromide and its 50 mol% solution in 2-methylpentane have been
studied in detail over the frequency range, 1 mHz?1 MHz, and a temperature range approaching
their liquid to glass transition. Features of the ~i! a-relaxation spectrum, ~ii! the Johari?Goldstein
relaxation process in the liquid state at low temperatures, with an asymmetric spectral shape, and
~iii! the temperature dependence of the relaxation dynamics have been determined and the effects of
weakening of the electrostatic interaction on these features examined. The high-frequency wing of
the loss spectrum of the a-relaxation is proportional to v2b. The dynamics of its a-relaxation
follows the Arrhenius equation initially at high temperatures and thereafter the Vogel?Fulcher?
Tamman equation. Alternative equations for the change in the relaxation rate have been discussed.
A decrease in the dipole?dipole interaction and reduction in the internal field in a solution with a
nonpolar solvent leads to a remarkable change in the shape of the relaxation spectra at high
frequencies such that the dielectric loss for the a-relaxation becomes proportional to v2ab, with a,
b,1. The relaxation spectra of iso-amyl bromide dissolved in 2-methylpentane follows the H?N
function and therefore behaves similar to a polymer, whereas for pure iso-amyl bromide follows the
Davidson?Cole behavior.
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http://people.tcd.ie/jvijDescription:
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Author: VIJ, JAGDISH KUMAR
Publisher:
American Institute of PhysicsType of material:
Journal ArticleSeries/Report no:
Journal of Chemical Physics;111;
24;
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Condensed matter physics, dielectric relaxationMetadata
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