Small-angle x-ray scattering of supercritical fluid Hg: Bi-impurity effect
Small-angle x-ray scattering of supercritical fluid Hg: Bi-impurity effect
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DOI：
10.1088/1742-6596/98/1/012002
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发表时间：
2008
期刊：
影响因子：
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通讯作者：
Y Kajihara;M Inui;K Matsuda;K Tamura
中科院分区：
文献类型：
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作者：
Y Kajihara;M Inui;K Matsuda;K Tamura
我们在日本SPirng-8上对超临界流体Hg-0.2%Bi和纯Hg体系进行了小角X射线散射和X射线透射测量。我们获得了两个样品在高达 1600 °C 和 200 MPa 的温度和压力下的低动量传递区域 (0.5< Q <3 nm−1) 的静态结构因子 S(Q)。仅在高温高压区域，从X射线透射推导出的S(Q)和密度均存在Bi杂质效应；对于 Hg-0.2%Bi 样品，在临界密度附近可以看到相分离的迹象。我们通过Ornstein-Zernike公式对S(Q)进行了分析，推导出长波长极限S(0)下的结构因子、相关长度ψ，以及相应的短程相关长度R = ψ≡/√S(0)。 R 的温度变化与每个样品中的密度变化非常相似。这一实验事实表明，R 的变化高度依赖于其金属性质，因为密度是流体汞及其杂质系统中电子特征最相关的参数。
We have carried out small-angle x-ray scattering and x-ray transmission measurements of supercritical fluid Hg-0.2%Bi and pure Hg systems at SPirng-8 in Japan. We have obtained the static structure factors S(Q) in the low-momentum transfer region (0.5< Q <3 nm−1) for both samples at temperatures and pressures up to 1600 °C and 200 MPa. A Bi-impurity effect can be seen in both S(Q) and density deduced from x-ray transmission, only in the high temperature and high pressure region; the sign of the phase separation is seen near the critical density for Hg-0.2%Bi sample. We have analyzed S(Q) by Ornstein-Zernike formula and deduced the structure factors in the long-wavelength limit S(0), correlation lengths ξ, and corresponding short-range correlation lengths R = ξ≡/√S(0). Temperature variation of R is very similar to that of the density in each sample. This experimental fact hints that the variation of R is highly dependent on its metallic nature because the density is the most relevant parameter for the electronic features in fluid Hg and its impurity systems.