Born’s valence force-field model for diamond at terapascals: Validity and implications for the primary pressure scale

Born’s valence force-field model (VFM) established a theoretical scheme for calculating the elasticity, zero-point optical mode, and lattice dynamics of diamond and diamond-structured solids. In particular, the model enabled the derivation of a numerical relation between the elastic moduli and the R...

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Autores principales:	Qingyang Hu, Ho-kwang Mao
Formato:	article
Lenguaje:	EN
Publicado:	AIP Publishing LLC 2021
Materias:	Nuclear and particle physics. Atomic energy. Radioactivity QC770-798
Acceso en línea:	https://doaj.org/article/46e408ae915f449f9f9a0836fc0a4d12
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spelling	oai:doaj.org-article:46e408ae915f449f9f9a0836fc0a4d122021-12-01T18:51:44ZBorn’s valence force-field model for diamond at terapascals: Validity and implications for the primary pressure scale2468-080X10.1063/5.0069479https://doaj.org/article/46e408ae915f449f9f9a0836fc0a4d122021-11-01T00:00:00Zhttp://dx.doi.org/10.1063/5.0069479https://doaj.org/toc/2468-080XBorn’s valence force-field model (VFM) established a theoretical scheme for calculating the elasticity, zero-point optical mode, and lattice dynamics of diamond and diamond-structured solids. In particular, the model enabled the derivation of a numerical relation between the elastic moduli and the Raman-active F2g mode for diamond. Here, we establish a relation between the diamond Raman frequency ω and the bulk modulus K through first-principles calculation, rather than extrapolation. The calculated K exhibits a combined uncertainty of less than 5.4% compared with the results obtained from the analytical equation of the VFM. The results not only validate Born’s classic model but also provide a robust K–ω functional relation extending to megabar pressures, which we use to construct a primary pressure scale through Raman spectroscopy and the crystal structure of diamond. Our computations also suggest that currently used pressure gauges may seriously overestimate pressures in the multi-megabar regime. A revised primary scale is urgently needed for such ultrahigh pressure experiments, with possible implications for hot superconductors, ultra-dense hydrogen, and the structure of the Earth’s core.Qingyang HuHo-kwang MaoAIP Publishing LLCarticleNuclear and particle physics. Atomic energy. RadioactivityQC770-798ENMatter and Radiation at Extremes, Vol 6, Iss 6, Pp 068403-068403-7 (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	Nuclear and particle physics. Atomic energy. Radioactivity QC770-798
spellingShingle	Nuclear and particle physics. Atomic energy. Radioactivity QC770-798 Qingyang Hu Ho-kwang Mao Born’s valence force-field model for diamond at terapascals: Validity and implications for the primary pressure scale
description	Born’s valence force-field model (VFM) established a theoretical scheme for calculating the elasticity, zero-point optical mode, and lattice dynamics of diamond and diamond-structured solids. In particular, the model enabled the derivation of a numerical relation between the elastic moduli and the Raman-active F2g mode for diamond. Here, we establish a relation between the diamond Raman frequency ω and the bulk modulus K through first-principles calculation, rather than extrapolation. The calculated K exhibits a combined uncertainty of less than 5.4% compared with the results obtained from the analytical equation of the VFM. The results not only validate Born’s classic model but also provide a robust K–ω functional relation extending to megabar pressures, which we use to construct a primary pressure scale through Raman spectroscopy and the crystal structure of diamond. Our computations also suggest that currently used pressure gauges may seriously overestimate pressures in the multi-megabar regime. A revised primary scale is urgently needed for such ultrahigh pressure experiments, with possible implications for hot superconductors, ultra-dense hydrogen, and the structure of the Earth’s core.
format	article
author	Qingyang Hu Ho-kwang Mao
author_facet	Qingyang Hu Ho-kwang Mao
author_sort	Qingyang Hu
title	Born’s valence force-field model for diamond at terapascals: Validity and implications for the primary pressure scale
title_short	Born’s valence force-field model for diamond at terapascals: Validity and implications for the primary pressure scale
title_full	Born’s valence force-field model for diamond at terapascals: Validity and implications for the primary pressure scale
title_fullStr	Born’s valence force-field model for diamond at terapascals: Validity and implications for the primary pressure scale
title_full_unstemmed	Born’s valence force-field model for diamond at terapascals: Validity and implications for the primary pressure scale
title_sort	born’s valence force-field model for diamond at terapascals: validity and implications for the primary pressure scale
publisher	AIP Publishing LLC
publishDate	2021
url	https://doaj.org/article/46e408ae915f449f9f9a0836fc0a4d12
work_keys_str_mv	AT qingyanghu bornsvalenceforcefieldmodelfordiamondatterapascalsvalidityandimplicationsfortheprimarypressurescale AT hokwangmao bornsvalenceforcefieldmodelfordiamondatterapascalsvalidityandimplicationsfortheprimarypressurescale
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Born’s valence force-field model for diamond at terapascals: Validity and implications for the primary pressure scale

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