### Abstract

This article gives an overview of excess-entropy scaling, the 1977 discovery by Rosenfeld that entropy

determines properties of liquids like viscosity, diffusion constant, and heat conductivity. We give

examples from computer simulations confirming this intriguing connection between dynamics and

thermodynamics, counterexamples, and experimental validations. Recent uses in application-related

contexts are reviewed, and theories proposed for the origin of excess-entropy scaling are briefly

summarized. It is shown that if two thermodynamic state points of a liquid have the same microscopic

dynamics, they must have the same excess entropy. In this case, the potential-energy function exhibits

a symmetry termed hidden scale invariance, stating that the ordering of the potential energies of

configurations is maintained if these are scaled uniformly to a different density. This property leads to

the isomorph theory, which provides a general framework for excess-entropy scaling and illuminates,

in particular, why this does not apply rigorously and universally. It remains an open question whether

all aspects of excess-entropy scaling and related regularities reflect hidden scale invariance in one

form or other.

determines properties of liquids like viscosity, diffusion constant, and heat conductivity. We give

examples from computer simulations confirming this intriguing connection between dynamics and

thermodynamics, counterexamples, and experimental validations. Recent uses in application-related

contexts are reviewed, and theories proposed for the origin of excess-entropy scaling are briefly

summarized. It is shown that if two thermodynamic state points of a liquid have the same microscopic

dynamics, they must have the same excess entropy. In this case, the potential-energy function exhibits

a symmetry termed hidden scale invariance, stating that the ordering of the potential energies of

configurations is maintained if these are scaled uniformly to a different density. This property leads to

the isomorph theory, which provides a general framework for excess-entropy scaling and illuminates,

in particular, why this does not apply rigorously and universally. It remains an open question whether

all aspects of excess-entropy scaling and related regularities reflect hidden scale invariance in one

form or other.

Originalsprog | Engelsk |
---|---|

Artikelnummer | 210901 |

Tidsskrift | Journal of Chemical Physics |

Vol/bind | 149 |

Udgave nummer | 21 |

Antal sider | 21 |

ISSN | 0021-9606 |

DOI | |

Status | Udgivet - 2018 |

### Bibliografisk note

This article has been found as a ’Free Version’ from the Publisher on January 7th 2019. When access to the article closes, please notify rucforsk@ruc.dk## Citer dette

Dyre, J. (2018). Perspective: Excess-entropy scaling.

*Journal of Chemical Physics*,*149*(21), [210901]. https://doi.org/10.1063/1.5055064