Dynamics of glass-forming liquids. X. Dielectric relaxation of 3-bromopentane as molecular probes in 3-methylpentane

Wei Huang, Shervin Shahriari, Ranko Richert

Research output: Contribution to journalArticle

24 Scopus citations

Abstract

The glass-forming liquids 3-bromopentane (3BP) and 3-methylpentane (3MP) are readily miscible across the entire composition range, although their polarities differ considerably. As noted by Berberian [J. Non-Cryst. Solids 131-133, 48 (1991)], the nearly matching molar volumes makes this binary system appear ideal for probe-sensitized measurements. We have performed a dielectric study of these mixtures in the range of 3BP mole fractions x from 2× 10-4 to 0.75. In the limit of low concentrations, x<0.5%, the dielectric loss peak of 3BP is slower by a factor of 2.5 relative to that of 3MP. Additionally, the relaxation behavior of the guest is more exponential than that of the host liquid. We interpret the distinct dynamics of the guest as a result of temporal averaging over the heterogeneous host dynamics, with the exchange time being near the longest structural time constant of the system.

Original languageEnglish (US)
Article number164504
JournalJournal of Chemical Physics
Volume123
Issue number16
DOIs
StatePublished - Nov 8 2005

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

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