6533b830fe1ef96bd129716e
RESEARCH PRODUCT
Mobilization upon Cooling
Thomas SpeckBenjamin StadtmüllerMartin AeschlimannRalf BechsteinSina MousavionSebastian BeckerSimon AeschlimannHans-joachim ElmersLu LyuAngelika Kühnlesubject
Phase transitionMaterials scienceCommunicationSTMDegrees of freedom (physics and chemistry)chemistry.chemical_elementmolecular self-assemblyGeneral Chemistry540Phase Transition | Very Important PaperCopperCommunicationsCatalysisAdsorptioninverse meltingchemistryphase transitionChemical physicsMolybdenumPhase (matter)MoleculeMonte Carlo simulationdescription
Abstract Phase transitions between different aggregate states are omnipresent in nature and technology. Conventionally, a crystalline phase melts upon heating as we use ice to cool a drink. Already in 1903, Gustav Tammann speculated about the opposite process, namely melting upon cooling. So far, evidence for such “inverse” transitions in real materials is rare and limited to few systems or extreme conditions. Here, we demonstrate an inverse phase transition for molecules adsorbed on a surface. Molybdenum tetraacetate on copper(111) forms an ordered structure at room temperature, which dissolves upon cooling. This transition is mediated by molecules becoming mobile, i.e., by mobilization upon cooling. This unexpected phenomenon is ascribed to the larger number of internal degrees of freedom in the ordered phase compared to the mobile phase at low temperatures.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2021-07-16 |