Structural studies of expanded fluid mercury.

膨胀流体汞的结构研究。

• 批准号: 03640338
• 负责人: HOSOKAWA Shinya
• 金额: $ 1.15万
• 依托单位: HIROSHIMA UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1991
• 资助国家: 日本
• 起止时间: 1991 至 1992
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-03640338/
• 关键词: Liquid Metal; Metal-nonmetal Transition; Liquid-Gas Critical Point; High Temperatures and Pressures; X-ray Diffraction; Mercury; Expanded Metal; Dense Vapor; 金属ー非金属転移

It is well known that liquid Hg is transformed to an insulating state when it is expanded up to the liquid-gas critical point (critical data of Hg: T_C=1478ﾟC, P_C=1673bar, d_c=5.8gcm^<-3>). A number of measurements of physical properties shows that, as the density is reduced, the metal-nonmetal (M-NM) transition starts to occur at a density of about 9 gcm^<-3>. The information on the atomic arrangement of expanded fluid Hg is quite important for understanding the M-NM transition. However, the diffraction experiments for expanded fluid Hg are not easy because the critical pressure is very high.We have performed X-ray diffraction measurement for expanded fluid Hg in the temperature and pressure range up to 1530ﾟC and 1980bar, in the density region from 13.55 to 6.8 gcm^<-3>, using the energy-dispersive method. For the measurements, we have developed a single-crystalline sapphire cell and a high-pressure vessel of our own design, and improved the method of the data analysis. It has been found that the volume expansion of liquid Hg in the metallic region is not accompanied by a uniform increase of interatomic distance, r_1, but mainly caused by a decrease of coordination number, N_1. When the M-NM transition is approached, the rate of decrease of N_1 becomes small and r_1 starts to elongate. In addition, we have carried out X-ray diffraction measurement for dense Hg vapor in the density range from 3.5 to 1.5 gcm^<-3>, and obtained the result that, as the density of vapor Hg is reduced, the position of the first peak of the interference function, S(k), shifts remarkably to lower-k side.

众所周知，液态汞在膨胀到液-气临界点时转变为绝缘态（汞的临界数据：T_C=1478ﾟC，P_C=1673bar，d_c=5.8gcm^<-3>）。物理性质的大量测量表明，随着密度降低，金属-非金属(M-NM)转变在约9gcm 2 -3 的密度下开始发生。膨胀流体 Hg 的原子排列信息对于理解 M-NM 转变非常重要。然而，膨胀流体汞的衍射实验并不容易，因为其临界压力非常高。我们采用能量色散法，在温度和压力高达1530°C、1980bar、密度范围为13.55至6.8 gcm^-3>的情况下对膨胀流体汞进行了X射线衍射测量。为了测量，我们开发了单晶蓝宝石电池和我们自己设计的高压容器，并改进了数据分析方法。研究发现，液态Hg在金属区的体积膨胀并非伴随着原子间距离r_1的均匀增大，而主要是由配位数N_1的减小引起的。当接近M-NM转变时，N_1的减小速率变小并且r_1开始拉长。此外，我们还对密度在3.5～1.5gcm^-3>范围内的浓汞蒸气进行了X射线衍射测量，得到的结果是，随着汞蒸气密度的降低，干涉函数S(k)的第一个峰的位置显着向低k侧移动。

项目成果

S.Hosokawa,T.Matsuoka and K.Tamura: "Xーray Diffraction Measurements for Expanded Liquid Mercury in the Metallic Region" J.Phys.:Condens.Matter. 3. 4443-4457 (1991)

S.Hosokawa、T.Matsuoka 和 K.Tamura：“金属区域膨胀液态汞的 X 射线衍射测量”J.Phys.:Condens.Matter。3. 4443-4457 (1991)

K.Tamura and S.Hosokawa: "Xーray Diffraction Measurements for Expanded Fluid selenium up to the Supercritical Region" Ber.Bunsenges.Phys.Chem.

K.Tamura 和 S.Hosokawa：“扩展流体硒至超临界区的 X 射线衍射测量”Ber.Bunsenges.Phys.Chem。

K.Tamura and S.Hosokawa: "Xーray Diffraction Measurements for Expanded Fluid Mercury around the Metalーnonmtal Transition Region" J.Physique IVーColloque C5. 1. 39-44 (1991)

K.Tamura 和 S.Hosokawa：“金属-非金属转变区域周围膨胀流体汞的 X 射线衍射测量”J.Physique IV-Colloque C5。1. 39-44 (1991)

K.Tamura and S.Hosokawa: "Xーray Diffraction Measurements for Expanded Fluid Mercury up to the Supercritical Region" J.Nonーcryst.Solids.

K.Tamura 和 S.Hosokawa：“膨胀流体汞至超临界区域的 X 射线衍射测量”J.Non-cryst.Solids。

田村 剛三郎、細川 伸也: "金属-非金属転移をおこす超臨床流体の構造解析" 日本結晶学会誌. 33. 217-223 (1991)

Gozaburo Tamura、Shinya Hosokawa：“导致金属-非金属转变的超临床流体的结构分析”日本晶体学会杂志 33. 217-223 (1991)。