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Theoretical predictions for low-temperature phases, softening of phonons and elastic stiffnesses, and electronic properties of sodium peroxide under high pressure
High-pressure phase stabilities up to 600 K and the related properties of Na(2)O(2) under pressures up to 300 GPa were investigated using first-principles calculations and the quasi-harmonic approximation. Two high-pressure phases of Na(2)O(2) that are thermodynamically and dynamically stable were p...
Autores principales: | , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
The Royal Society of Chemistry
2019
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9072567/ https://www.ncbi.nlm.nih.gov/pubmed/35529358 http://dx.doi.org/10.1039/c9ra03735g |
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author | Jimlim, Pornmongkol Tsuppayakorn-aek, Prutthipong Pakornchote, Teerachote Ektarawong, Annop Pinsook, Udomsilp Bovornratanaraks, Thiti |
author_facet | Jimlim, Pornmongkol Tsuppayakorn-aek, Prutthipong Pakornchote, Teerachote Ektarawong, Annop Pinsook, Udomsilp Bovornratanaraks, Thiti |
author_sort | Jimlim, Pornmongkol |
collection | PubMed |
description | High-pressure phase stabilities up to 600 K and the related properties of Na(2)O(2) under pressures up to 300 GPa were investigated using first-principles calculations and the quasi-harmonic approximation. Two high-pressure phases of Na(2)O(2) that are thermodynamically and dynamically stable were predicted consisting of the Amm2 (distorted P6̄2m) and the P2(1)/c structures, which are stable at low temperature in the pressure range of 0–22 GPa and 22–28 GPa, respectively. However, the P6̄2m and Pbam structures become the most stable instead of the Amm2 and P2(1)/c structures at the elevated temperatures, respectively. Interestingly, the softening of some phonon modes and the decreasing of some elastic stiffnesses in the Amm2 structure were also predicted in the pressure ranges of 2–3 GPa and 9–10 GPa. This leads to the decreasing of phonon free energy and the increasing of the ELF value in the same pressure ranges. The HSE06 band gaps suggest that all phases are insulators, and they increase with increasing pressure. Our findings provide the P–T phase diagram of Na(2)O(2), which may be useful for investigating the thermodynamic properties and experimental verification. |
format | Online Article Text |
id | pubmed-9072567 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2019 |
publisher | The Royal Society of Chemistry |
record_format | MEDLINE/PubMed |
spelling | pubmed-90725672022-05-06 Theoretical predictions for low-temperature phases, softening of phonons and elastic stiffnesses, and electronic properties of sodium peroxide under high pressure Jimlim, Pornmongkol Tsuppayakorn-aek, Prutthipong Pakornchote, Teerachote Ektarawong, Annop Pinsook, Udomsilp Bovornratanaraks, Thiti RSC Adv Chemistry High-pressure phase stabilities up to 600 K and the related properties of Na(2)O(2) under pressures up to 300 GPa were investigated using first-principles calculations and the quasi-harmonic approximation. Two high-pressure phases of Na(2)O(2) that are thermodynamically and dynamically stable were predicted consisting of the Amm2 (distorted P6̄2m) and the P2(1)/c structures, which are stable at low temperature in the pressure range of 0–22 GPa and 22–28 GPa, respectively. However, the P6̄2m and Pbam structures become the most stable instead of the Amm2 and P2(1)/c structures at the elevated temperatures, respectively. Interestingly, the softening of some phonon modes and the decreasing of some elastic stiffnesses in the Amm2 structure were also predicted in the pressure ranges of 2–3 GPa and 9–10 GPa. This leads to the decreasing of phonon free energy and the increasing of the ELF value in the same pressure ranges. The HSE06 band gaps suggest that all phases are insulators, and they increase with increasing pressure. Our findings provide the P–T phase diagram of Na(2)O(2), which may be useful for investigating the thermodynamic properties and experimental verification. The Royal Society of Chemistry 2019-10-01 /pmc/articles/PMC9072567/ /pubmed/35529358 http://dx.doi.org/10.1039/c9ra03735g Text en This journal is © The Royal Society of Chemistry https://creativecommons.org/licenses/by-nc/3.0/ |
spellingShingle | Chemistry Jimlim, Pornmongkol Tsuppayakorn-aek, Prutthipong Pakornchote, Teerachote Ektarawong, Annop Pinsook, Udomsilp Bovornratanaraks, Thiti Theoretical predictions for low-temperature phases, softening of phonons and elastic stiffnesses, and electronic properties of sodium peroxide under high pressure |
title | Theoretical predictions for low-temperature phases, softening of phonons and elastic stiffnesses, and electronic properties of sodium peroxide under high pressure |
title_full | Theoretical predictions for low-temperature phases, softening of phonons and elastic stiffnesses, and electronic properties of sodium peroxide under high pressure |
title_fullStr | Theoretical predictions for low-temperature phases, softening of phonons and elastic stiffnesses, and electronic properties of sodium peroxide under high pressure |
title_full_unstemmed | Theoretical predictions for low-temperature phases, softening of phonons and elastic stiffnesses, and electronic properties of sodium peroxide under high pressure |
title_short | Theoretical predictions for low-temperature phases, softening of phonons and elastic stiffnesses, and electronic properties of sodium peroxide under high pressure |
title_sort | theoretical predictions for low-temperature phases, softening of phonons and elastic stiffnesses, and electronic properties of sodium peroxide under high pressure |
topic | Chemistry |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9072567/ https://www.ncbi.nlm.nih.gov/pubmed/35529358 http://dx.doi.org/10.1039/c9ra03735g |
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