Local structure of molten AuGa2 under pressure: Evidence for coordination change and planetary implications

Abstract In situ x-ray diffraction measurements and inverse Monte Carlo simulations of pair distribution functions were used to characterize the local structure of molten AuGa2 up to 16 GPa and 940 K. Our results document systematic changes in liquid structure due to a combination of bond compressio...

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Autores principales:	Bora Kalkan, Budhiram Godwal, Selva Vennila Raju, Raymond Jeanloz
Formato:	article
Lenguaje:	EN
Publicado:	Nature Portfolio 2018
Materias:	Medicine R Science Q
Acceso en línea:	https://doaj.org/article/6528c407025347debb685c996b20d583
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spelling	oai:doaj.org-article:6528c407025347debb685c996b20d5832021-12-02T15:08:30ZLocal structure of molten AuGa2 under pressure: Evidence for coordination change and planetary implications10.1038/s41598-018-25297-92045-2322https://doaj.org/article/6528c407025347debb685c996b20d5832018-05-01T00:00:00Zhttps://doi.org/10.1038/s41598-018-25297-9https://doaj.org/toc/2045-2322Abstract In situ x-ray diffraction measurements and inverse Monte Carlo simulations of pair distribution functions were used to characterize the local structure of molten AuGa2 up to 16 GPa and 940 K. Our results document systematic changes in liquid structure due to a combination of bond compression and coordination increase. Empirical potential structure refinement shows the first-neighbor coordination of Ga around Au and of Au around Ga to increase from about 8 to 10 and 4 to 5, respectively between 0 and 16 GPa, and the inferred changes in liquid structure can explain the observed melting-point depression of AuGa2 up to 5 GPa. As intermetallic AuGa2 is an analogue for metallic SiO2 at much higher pressures, our results imply that structural changes documented for non-metallic silicate melts below 100 GPa are followed by additional coordination changes in the metallic state at pressures in the 0.2–1 TPa range achieved inside large planets.Bora KalkanBudhiram GodwalSelva Vennila RajuRaymond JeanlozNature PortfolioarticleMedicineRScienceQENScientific Reports, Vol 8, Iss 1, Pp 1-10 (2018)
institution	DOAJ
collection	DOAJ
language	EN
topic	Medicine R Science Q
spellingShingle	Medicine R Science Q Bora Kalkan Budhiram Godwal Selva Vennila Raju Raymond Jeanloz Local structure of molten AuGa2 under pressure: Evidence for coordination change and planetary implications
description	Abstract In situ x-ray diffraction measurements and inverse Monte Carlo simulations of pair distribution functions were used to characterize the local structure of molten AuGa2 up to 16 GPa and 940 K. Our results document systematic changes in liquid structure due to a combination of bond compression and coordination increase. Empirical potential structure refinement shows the first-neighbor coordination of Ga around Au and of Au around Ga to increase from about 8 to 10 and 4 to 5, respectively between 0 and 16 GPa, and the inferred changes in liquid structure can explain the observed melting-point depression of AuGa2 up to 5 GPa. As intermetallic AuGa2 is an analogue for metallic SiO2 at much higher pressures, our results imply that structural changes documented for non-metallic silicate melts below 100 GPa are followed by additional coordination changes in the metallic state at pressures in the 0.2–1 TPa range achieved inside large planets.
format	article
author	Bora Kalkan Budhiram Godwal Selva Vennila Raju Raymond Jeanloz
author_facet	Bora Kalkan Budhiram Godwal Selva Vennila Raju Raymond Jeanloz
author_sort	Bora Kalkan
title	Local structure of molten AuGa2 under pressure: Evidence for coordination change and planetary implications
title_short	Local structure of molten AuGa2 under pressure: Evidence for coordination change and planetary implications
title_full	Local structure of molten AuGa2 under pressure: Evidence for coordination change and planetary implications
title_fullStr	Local structure of molten AuGa2 under pressure: Evidence for coordination change and planetary implications
title_full_unstemmed	Local structure of molten AuGa2 under pressure: Evidence for coordination change and planetary implications
title_sort	local structure of molten auga2 under pressure: evidence for coordination change and planetary implications
publisher	Nature Portfolio
publishDate	2018
url	https://doaj.org/article/6528c407025347debb685c996b20d583
work_keys_str_mv	AT borakalkan localstructureofmoltenauga2underpressureevidenceforcoordinationchangeandplanetaryimplications AT budhiramgodwal localstructureofmoltenauga2underpressureevidenceforcoordinationchangeandplanetaryimplications AT selvavennilaraju localstructureofmoltenauga2underpressureevidenceforcoordinationchangeandplanetaryimplications AT raymondjeanloz localstructureofmoltenauga2underpressureevidenceforcoordinationchangeandplanetaryimplications
_version_	1718388124600500224

Local structure of molten AuGa2 under pressure: Evidence for coordination change and planetary implications

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