Mixed Molecular and Atomic Phase of Dense Hydrogen

被引：235

作者：

Howie, Ross T. ^{[1
,2
]}

Guillaume, Christophe L. ^{[1
,2
]}

Scheler, Thomas ^{[1
,2
]}

Goncharov, Alexander F. ^{[3
]}

Gregoryanz, Eugene ^{[1
,2
]}

机构：

[1] Univ Edinburgh, Ctr Sci Extreme Condit, Edinburgh EH9 3JZ, Midlothian, Scotland

[2] Univ Edinburgh, Sch Phys & Astron, Edinburgh EH9 3JZ, Midlothian, Scotland

[3] Carnegie Inst Washington, Geophys Lab, Washington, DC 20015 USA

来源：

PHYSICAL REVIEW LETTERS | 2012年 / 108卷 / 12期

基金：

英国工程与自然科学研究理事会; 美国国家科学基金会;

关键词：

SOLID HYDROGEN; MEGABAR PRESSURES; METALLIC HYDROGEN; TRANSITION; FLUID; GPA; DEUTERIUM; H2O;

D O I：

10.1103/PhysRevLett.108.125501

中图分类号：

O4 [物理学];

学科分类号：

0702 ;

摘要：

We used Raman and visible transmission spectroscopy to investigate dense hydrogen (deuterium) up to 315 (275) GPa at 300 K. At around 200 GPa, we observe the phase transformation, which we attribute to phase III, previously observed only at low temperatures. This is succeeded at 220 GPa by a reversible transformation to a new phase, IV, characterized by the simultaneous appearance of the second vibrational fundamental and newlow-frequency phonon excitations and a dramatic softening and broadening of the first vibrational fundamental mode. The optical transmission spectra of phase IV show an overall increase of absorption and a closing band gap which reaches 1.8 eVat 315 GPa. Analysis of the Raman spectra suggests that phase IV is a mixture of graphenelike layers, consisting of elongated H-2 dimers experiencing large pairing fluctuations, and unbound H-2 molecules.

引用

页数：5

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