Determination of the thermodynamic scaling exponent for relaxation in liquids from static ambient-pressure quantities.

  title={Determination of the thermodynamic scaling exponent for relaxation in liquids from static ambient-pressure quantities.},
  author={Riccardo Casalini and C. Michael Roland},
  journal={Physical review letters},
  volume={113 8},
An equation is derived that expresses the thermodynamic scaling exponent, γ, which superposes relaxation times τ and other measures of molecular mobility determined over a range of temperatures and densities, in terms of static physical quantities. The latter are available in the literature or can be measured at ambient pressure. We show for 13 materials, both molecular liquids and polymers, that the calculated γ are equivalent to the scaling exponents obtained directly by superpositioning. The… 

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  • Rev. Lett. 29, 85 (1972); J. R. McColl, Phys. Lett. 38A, 55
  • 1972


  • 139, 184506
  • 2013


  • Rev. E 69, 062501
  • 2004

Macromolecules 40

  • 3631
  • 2007


  • 39, 3369
  • 1963

Macromolecules 44

  • 6928
  • 2011

Solids 262

  • 258 (2000); 351, 3163
  • 2005