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Structural and Optical Studies of High-Pressure Phases of Solid Oxygen

固体氧高压相的结构和光学研究

基本信息

批准号：
10440093
负责人：
AKAHAMA Yuichi
金额：
$ 7.62万
依托单位：
Himeji Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

项目摘要

1. By using high-energy and high-brilliance synchrotron radiation sources in Spring-8 and ESRF, an energy-dispersive powder X-ray diffraction study on solid oxygen has been carried out up to 220 GPa at low temperature due to 12 Pa at low temperature of 19 K. The phase transition to the ζmetallic high-pressure phase, which had been revealed by our previous experiments, was reconfirmed at 96 GPa in this study. The transition was sluggish, and was accompanied by the discontinuous band gap closure, which was observed by our infrared absorption measurement. The transition was first-order. The metallic phase was stable up to 220 GPa. The phase diagram in the low temperature and high pressure region was established. The magnetic ordering in the αand δphases was suggested from an enha cement of the anisotropy of lattice compression.2. Single-crystals of the ε-OィイD22ィエD2 phase were prepared by a strain anneal method under a condition of 25 GPa and 650 K and were used for infrared absorption experiments under pressure up to 92 GPa. The spectrum at 92 GPa exhibited a drastic change corresponding to the metallization. The frequency of the IR-active vibron fundamentals and libron were obtained as a function of pressure to 86 GPa at room temperature. Raman scattering measurements was also carried out at room temperature. From the spectroscopic data of molecular vibration, the inter- and intra molecular interaction, and further the structure of the εphase were discussed. These results suggested that a molecular state is rather stable in the metallic ζphase.3. Structural analysis of a single crystal of the β phase (R3m) suggested that the oxygen molecules were disordered under three-fold axis symmetry. The disorder state may be related to the magnetic structure of the phase.

1.利用Spring-8和ESRF的高能高亮度同步辐射光源，对固体氧进行了能量色散粉末X射线衍射研究，其压力由19 K低温时的12 Pa提高到220 GPa。在本研究中，在96 GPa下再次证实了我们以前的实验所揭示的向非金属高压相的相变。通过红外吸收测量，我们观察到了这种转变是缓慢的，并且伴随着不连续的带隙闭合。过渡是第一顺序的。金属相在高达220 GPa的压力下是稳定的。建立了低温高压区的相图。从晶格压缩各向异性的增强可以推测α和δ相的磁有序性.在25 GPa和650 K的条件下通过应变退火方法制备了ε-O_（22）O在92 GPa下的光谱表现出对应于金属化的剧烈变化。在室温下，红外活性振动子的基本原理和libron的频率作为压力的函数，以86 GPa。拉曼散射测量也在室温下进行。根据分子振动光谱数据，讨论了分子间和分子内相互作用，进而讨论了ε相的结构。这些结果表明，在金属相中，分子态是相当稳定的.对β相（R3 m）单晶的结构分析表明，氧分子在三重轴对称下是无序的。无序状态可能与相的磁结构有关。