Dissipation in monotonic and non-monotonic relaxation to equilibrium

Charlotte F. Petersen*, Denis J. Evans, Stephen R. Williams

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

4 Citations (Scopus)


Using molecular dynamics simulations, we study field free relaxation from a non-uniform initial density, monitored using both density distributions and the dissipation function. When this density gradient is applied to colour labelled particles, the density distribution decays to a sine curve of fundamental wavelength, which then decays conformally towards a uniform distribution. For conformal relaxation, the dissipation function is found to decay towards equilibrium monotonically, consistent with the predictions of the relaxation theorem. When the system is initiated with a more dramatic density gradient, applied to all particles, non-conformal relaxation is seen in both the dissipation function and the Fourier components of the density distribution. At times, the system appears to be moving away from a uniform density distribution. In both cases, the dissipation function satisfies the modified second law inequality, and the dissipation theorem is demonstrated.

Original languageEnglish
Article number074107
Number of pages8
JournalJournal of Chemical Physics
Issue number7
Publication statusPublished - 21 Feb 2016
MoE publication typeA1 Journal article-refereed


  • molecular dynamics simulations


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