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dc.contributor.authorVIJ, JAGDISH KUMAR
dc.date.accessioned2010-08-18T15:30:46Z
dc.date.available2010-08-18T15:30:46Z
dc.date.issued2001
dc.date.submitted2001en
dc.identifier.citationKalinovskaya, O.E., Vij, J.K., Nonexponential dielectric relaxation dynamics in supercooled liquid and glassy states of isoamyl bromide and 2-methylpentane mixtures, Journal of Chemical Physics, 114, 8, 2001, 2718 - 2726en
dc.identifier.otherY
dc.identifier.urihttp://hdl.handle.net/2262/40539
dc.descriptionPUBLISHEDen
dc.description.abstractThe dielectric spectra of mixtures of the polar solute isoamyl bromide in 2-methylpentane have been investigated in the frequency range 1 mHz to 1 MHz and in the temperature range approaching the glass transition temperature. The results obtained from the spectra are compared with those obtained recently [J. Chem. Phys. 111, 10979 (1999)] on pure isoamyl bromide. It is found that on increasing dilution with the nonpolar solvent, the width of the curves of the dielectric spectra increase significantly, and this is reflected in the increase in the nonexponential nature of the relaxation dynamics. This is found to be a consequence of the decrease in the cooperativity of the relaxation dynamics and or an increase in the heterogeneity of the solution. The data are found to fit the Havriliak?Negami equation extremely well. The data at low and high frequencies also fits the "universal law," since the latter is a low and high frequencies limiting case of the Havriliak?Negami equation. The scaling parameters of this law are calculated for the 25 mol % solution of isoamyl bromide in 2-methylpentane, and these are shown to experimentally relate to the H?N parameters. The stretched exponential parameter, , is estimated as a function of the temperature and is shown to follow the equation a(T?T0). Vogel?Fulcher?Tammann equation fits the data of the relaxation peak frequency as a function of the inverse of absolute temperature for the various mixtures quite well, this being possibly a consequence of the temperature dependence of the stretched exponential parameter. The predictions from the mode coupling theory and those by Bertrand and Souletie are verified with the exception that the exponent is found to be much greater than predicted by these theories. The relative predominance of the Johari?Goldstein process in isoamyl bromide increases initially with dilution with 2-methylpentane and then disappears as the number density of the independent relaxors increases with further dilution.en
dc.description.sponsorshipWe thank the American Petroleum Research Fund of the American Chemical Society, PRF #33221-AC7, for funding this work. We are extremely grateful to Professor G. P. Johari and Professor B. K. P. Scaife for the stimulating discussions.en
dc.format.extent2718en
dc.format.extent2726en
dc.language.isoenen
dc.publisherAmerican Institute of Physicsen
dc.relation.ispartofseriesJournal of Chemical Physics;
dc.relation.ispartofseries114;
dc.relation.ispartofseries8;
dc.rightsYen
dc.subjectCondensed matter physicsen
dc.subjectdielectric relaxationen
dc.titleNonexponential dielectric relaxation dynamics in supercooled liquid and glassy states of isoamyl bromide and 2-methylpentane mixturesen
dc.typeJournal Articleen
dc.type.supercollectionscholarly_publicationsen
dc.type.supercollectionrefereed_publicationsen
dc.identifier.peoplefinderurlhttp://people.tcd.ie/jvij
dc.identifier.rssinternalid24425
dc.identifier.rssurihttp://dx.doi.org/10.1063/1.1338511en


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