Experimental Studies on Crystal Structure and Electronic Properties of High-pressure Phases of Oxygen

[1]通过在Spring-8同步辐射光源上进行粉末X射线衍射实验，在0.5~280 Gpa的较宽压力范围内采集了固体氧的衍射数据，并进行了Rietveld分析。我们发现固体氧的S相的结构是由(O_2)_4团簇组成的，并且团簇结构在100 Gpa的压力下是稳定的。(O_2)_4团簇的观察是继臭氧之后发现了氧的同素异形体。我们目前的分子振动光谱数据解释了它的结构。这些结果在戈登研究会议(2006)上公布，并在新闻发布会上展示。用逆蒙特卡罗方法(提交给Phys)阐明了氧的超临界流体的局部结构与氧分子的取向相关。[2]通过分子科学研究所的UVSOR吸收实验，…收集了凝聚氧的电子光谱在0.3~18 Gpa的较宽压力范围内，观察到了吸收边和双分子吸收带随压力的变化。[3]用拉曼散射和红外吸收实验研究了(O_2)_4团簇在297K下的ε相振动光谱，从光谱的压力演化确定了该团簇的9个拉曼活性模式和6个红外活性模式为基波振动。模型的个数与聚类的因素群分析结果一致。[4]为了研究超高压下固体氧的光学性质，发展了一种用金刚石顶拉曼压力计测量超高压下固体氧的压强的新方法。在220 Gpa的Al和107 Gpa的P中发现了两个新的高压相。较少

[1] By powder x-ray diffraction experiments using the synchrotron radiation source at Spring-8, the diffraction data of solid oxygen were collected in a wide pressure range from 0.5 GPa to 280 GPa, and the Rietveld analyses was carried out. We have revealed that the structure of the s phase of solid oxygen is comprised of (O_2)_4 clusters and the cluster structure is stable at pressure up to 100 GPa. The observation of the (O_2)_4 cluster is a discovery of allotrope of oxygen following upon ozone. The structure was explained our present spectroscopic data of molecular vibrations. These results were presented at the Gordon Research Conference (2006) and also press-showed. The local structure of supercritical fluid of oxygen was also clarified to have an orientational correlation of oxygen molecules by Reverse Monte Carlo method (submitted to Phys. Rev. Lett.).[2] By UVSOR absorption experiment at the Institute for Molecular Science, electronic spectra of condensed oxygen were collected … More in a wide pressure range from 0.3 GPa to 18 GPa, and absorption edge and the two-molecule absorption bands were observed as a function of pressure. New absorption band was also clarified at the ultraviolet region and assigned as the Herzberg band.[3] The vibrational spectra of (O_2)_4 clusters in the ε phase of solid oxygen have been studied by Raman scattering and IR absorption experiments using a single crystal at 297 K. From the pressure evolutions of the spectra, nine Raman active and six IR active modes were identified as the fundamental vibrations of the cluster. The number of the modes was consistent with the result of the factor group analysis on the cluster. An abnormal softening of the Raman and IR active high-frequency modes was also clarified in the pressure dependence at lower pressures.[4] New pressure determination method using the diamond anvil Raman gauge was developed in the multimegabar pressure range (380 GPa >P>200 GPa) for the optical study of solid oxygen under ultrahigh-pressure and two new high-pressure phases were discovered in Al at 220 GPa and phosphorus at 107 GPa. Less