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Superionicity, disorder, and bandgap closure in dense hydrogen chloride

Hydrogen bond networks play a crucial role in biomolecules and molecular materials such as ices. How these networks react to pressure directs their properties at extreme conditions. We have studied one of the simplest hydrogen bond formers, hydrogen chloride, from crystallization to metallization, c...

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Detalles Bibliográficos
Autores principales: Binns, Jack, Hermann, Andreas, Peña-Alvarez, Miriam, Donnelly, Mary-Ellen, Wang, Mengnan, Kawaguchi, Saori Imada, Gregoryanz, Eugene, Howie, Ross T., Dalladay-Simpson, Philip
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Association for the Advancement of Science 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8442878/
https://www.ncbi.nlm.nih.gov/pubmed/34516915
http://dx.doi.org/10.1126/sciadv.abi9507
Descripción
Sumario:Hydrogen bond networks play a crucial role in biomolecules and molecular materials such as ices. How these networks react to pressure directs their properties at extreme conditions. We have studied one of the simplest hydrogen bond formers, hydrogen chloride, from crystallization to metallization, covering a pressure range of more than 2.5 million atmospheres. Following hydrogen bond symmetrization, we identify a previously unknown phase by the appearance of new Raman modes and changes to x-ray diffraction patterns that contradict previous predictions. On further compression, a broad Raman band supersedes the well-defined excitations of phase V, despite retaining a crystalline chlorine substructure. We propose that this mode has its origin in proton (H(+)) mobility and disorder. Above 100 GPa, the optical bandgap closes linearly with extrapolated metallization at 240(10) GPa. Our findings suggest that proton dynamics can drive changes in these networks even at very high densities.