ISIS Neutron and Muon Source Data Journal

Discrete breathers in barocaloric ammonium salts

Abstract: Barocaloric materials, which can be cycled between high- and low-entropy phases by applying pressure, provide an important, environmentally friendly alternative to vapour-compression refrigeration. However, a far greater understanding of the structural origins of the entropy change is needed in order to systematically improve these materials? properties to the point of commercial value. One unexplored route to increasing the entropy is to take advantage of ?discrete breathers?, intrinsically localised modes that can form as the result of anharmonic interactions between the molecular components of a crystal. Here we propose a detailed exploration of these modes in a simple barocaloric, ND4I, in which they have been theoretically predicted but never experimentally observed. Our results will demonstrate whether these modes can be used as a design tool for entropic materials. We will further compare them against molecular simulations as part of a wider ISIS-funded PhD project on molecular modelling of inelastic and quasielastic scattering data.

Principal Investigator: Dr Anthony Phillips
Local Contact: Dr Helen Walker
Experimenter: Mr Shiqi Gan
Experimenter: Mr Peter Nguyen-Minh

DOI: 10.5286/ISIS.E.RB2410724

ISIS Experiment Number: RB2410724

Publisher: STFC ISIS Neutron and Muon Source

Data format: RAW/Nexus
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Data Citation

The recommended format for citing this dataset in a research publication is as:
[author], [date], [title], [publisher], [doi]

For Example:
Dr Anthony Phillips et al; (2025): Discrete breathers in barocaloric ammonium salts, STFC ISIS Neutron and Muon Source, https://doi.org/10.5286/ISIS.E.RB2410724

Data is released under the CC-BY-4.0 license.