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

利用同步辐射源Spring-8进行粉末x射线衍射实验，在0.5 ~ 280 GPa的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相结构是由（O_2）_4团簇组成的，并且团簇结构在高达100gpa的压力下是稳定的。对（O_2）_4星团的观测是继臭氧之后氧的同素异形体的发现。用现有的分子振动光谱数据解释了其结构。这些结果在戈登研究会议（2006年）上发表，并被媒体报道。超临界氧流体的局部结构也通过反向蒙特卡罗方法澄清了氧分子的取向相关性(提交物理。(1)。[2]通过分子科学研究所的紫外紫外吸收实验，在0.3 ~ 18 GPa的宽压力范围内收集了凝聚氧的电子能谱，并观察到吸收边和双分子吸收带随压力的变化规律。在紫外区也发现了新的吸收带，并将其命名为赫茨伯格带用拉曼散射和红外吸收实验研究了固态氧ε相（O_2）_4团簇在297 K下的振动光谱。根据光谱的压力演化，确定了9种拉曼主动模式和6种红外主动模式是星团的基本振动。模式数与聚类因子群分析结果一致。在较低的压力依赖性下，拉曼和红外有源高频模式的异常软化也得到了澄清在超高压条件下，在380 GPa、>P、>、200 GPa的兆巴压力范围内，采用金刚石砧拉曼计测定固体氧的光学压力，在220 GPa的Al和107 GPa的磷中发现了两个新的高压相。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