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Updated: Aug 19, 2025

Ethylene Polymerizations Using Parallel Pressure Reactors and a Kinetic Analysis of Chain Transfer Polymerization
Published on: November 27, 2015
Excitations follow (or lead?) density scaling in propylene carbonate
John P Stoppleman1, Jesse G McDaniel1, Marcus T Cicerone1
1Department of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332, USA, https://www.chemistry.gatech.edu.
Abstract:
Structural excitations that enable interbasin (IB) barrier crossings on a potential energy landscape are thought to play a facilitating role in the relaxation of liquids. Here, we show that the population of these excitations exhibits the same density scaling observed for α relaxation in propylene carbonate, even though they are heavily influenced by intramolecular modes. We also find that IB crossing modes exhibit a Grüneisen parameter (γG) that is approximately equivalent to the density scaling parameter γTS. These observations suggest that the well-documented relationship between γG and γTS may be a direct result of the pressure dependence of the frequency of unstable (relaxation) modes associated with IB motion.
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