Centre for Viscous Liquid Dynamics (Glass and Time) develops new theory for the thermodynamics of freezing and melting

Although the freezing of liquids and melting of crystals are fundamental in many areas of the sciences, even simple properties like the temperature–pressure relation along the melting line cannot be predicted today. Researchers at the Center for Viscous Liquid Dynamics (Glass and Time) have developed a theory in which the properties of the coexisting crystal and liquid phases at a single thermodynamic point provide the basis for calculating the pressure, density and entropy of fusion as functions of temperature along the melting line.

The theory has been published in Nature Communications.

“When you increase pressure, the melting temperature typically rises. At one atmospheric pressure, iron will melt at 1,538 degrees Celsius, but at the high pressure of the Earth’s core, iron first becomes liquid at above 5,000 degrees,” says first author, Ulf Rørbæk Pedersen, a post-doctoral fellow at the centre.

Read more at Videnskab.dk (in Danish)

In the long run, the scientists hope that the theory can be used to model the extreme conditions in the cores of, e.g., exo planets. For exo planets, which circle around stars other than the Sun, it would be interesting to know how long it would take for the planet to give off its heat because that impacts how long the planet is warm enough to have liquid water on its surface, which is a prerequisite for life.

The Glass and Time center was established with a grant from the DNRF. Although the grant period ended in 2015, the center continues to publish research results from that period.