Pressure-induced structural transitions in MgH2 -: art. no. 175506

被引：184

作者：

Vajeeston, P ^{[1
]}

Ravindran, P ^{[1
]}

Kjekshus, A ^{[1
]}

Fjellvåg, H ^{[1
]}

机构：

[1] Univ Oslo, Dept Chem, N-0315 Oslo, Norway

来源：

PHYSICAL REVIEW LETTERS | 2002年 / 89卷 / 17期

关键词：

D O I：

10.1103/PhysRevLett.89.175506

中图分类号：

O4 [物理学];

学科分类号：

0702 ;

摘要：

The stability of MgH2 has been studied up to 20 GPa using density-functional total-energy calculations. At ambient pressure alpha-MgH2 takes a TiO2-rutile-type structure. alpha-MgH2 is predicted to transform into gamma-MgH2 at 0.39 GPa. The calculated structural data for alpha- and gamma-MgH2 are in very good agreement with experimental values. At equilibrium the energy difference between these modifications is very small, and as a result both phases coexist in a certain volume and pressure field. Above 3.84 GPa gamma-MgH2 transforms into beta-MgH2, consistent with experimental findings. Two further transformations have been identified at still higher pressure: (i) beta- to delta-MgH2 at 6.73 GPa and (ii) delta- to epsilon-MgH2 at 10.26 GPa.

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页数：4

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