Investigation of bulk and surface melting from microscopic view point

从微观角度研究块体和表面熔化

• 批准号: 09640598
• 负责人: YOKOYAMA Toshihiko
• 金额: $ 2.05万
• 依托单位: The University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1997
• 资助国家: 日本
• 起止时间: 1997 至 1998
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09640598/
• 关键词: melting; surface melting; XAFS (X-ray-absorption fine structure); path integral; surface vibration; EXAFS; エピタキシ-; 薄膜; 非調和振動; embedded atom法

Although melting transition is commonly observable in our dairy lives, the understanding of melting is still an open question in the microscopic point of view. Since anharmonic vibration plays an essential role, the EXAFS (extended x-ray-absorption fine structure) spectroscopy is useful to investigate the melting phenomenon from the view point of local structure and anharmonic vibration. In this work, we have first of all examined thermal properties of bulk materials at low temperature using EXAFS by estimating interatomic potentials with the quantum statistical approach. Here the path-integral effective-potential (PIEP) method was employed. In order to apply the PIEP method to metals, the embedded atom method was formulated and combined. In experiments, we have developed new ultrahigh vacuum chmaber for surface EXAPS measurements from low to high temperatures. We have investigated anisotropic anharmonic surface vibrations of ultrathin epitaxial flims such as KBr on KCl and Ni and Cu on graphite by means of temperature-dependent EXAFS measurements.

虽然融化转变在日常生活中是常见的现象，但从微观角度对融化的理解仍然是一个悬而未决的问题。由于非谐振动起着至关重要的作用，扩展X射线吸收精细结构（EXAFS）光谱是有用的，从局部结构和非谐振动的角度来研究熔化现象。在这项工作中，我们首先研究了在低温下使用EXAFS通过估计原子间相互作用势与量子统计方法的块状材料的热性质。本文采用路径积分有效电位法（PIEP）。为了将PIEP方法应用于金属，将嵌入原子方法公式化并结合起来。在实验中，我们已经开发了新的表面EXAPS测量从低到高的温度下的可调真空chmaber。本文用变温EXAFS方法研究了KBr/KCl和Ni、Cu/石墨外延膜的各向异性非谐表面振动。

项目成果

H.Hamamatsu, T.Yokoyama 他: "Surface structure of cesium adsorption on si(001)2X1 surface" Phys-Rev.B. 57(印刷中). (1998)

H. Hamamatsu、T. Yokoyama 等人：“si(001)2X1 表面上铯吸附的表面结构”Phys-Rev.B. (1998 年)。

横山 利彦: "Path integral effective potential theory for EXAFS cumulants compared to the second-order perturbation" J.Synchrotron Radiation. (印刷中).

Toshihiko Yokoyama：“与二阶扰动相比的 EXAFS 累积量的路径积分有效势理论”J. Synchrotron Radiation（正在出版）。

横山 利彦: "Effective potential method applied to EXAFS Debye-Waller factors of molecules and solids" Proc.Int.Conf.Path Integral 98. (印刷中).

Toshihiko Yokoyama：“适用于分子和固体的 EXAFS Debye-Waller 因子的有效势方法”Proc.Int.Conf.Path Integral 98。（出版中）。

T.Yokoyama: "Path-integral effective-potential theory for EXAFS cumulants compared to the second-order perturbation" J.Synchrotron Rad.(in press).

T.Yokoyama：“与二阶扰动相比的 EXAFS 累积量的路径积分有效势理论”J.Synchrotron Rad.（出版中）。

M.Kiguchi, T.Yokoyama, T.Tsuduki, S.Terada, Y.Kitajima and T.Ohta: "Heteroepitaxial growth of KCl on a cleaved (001) face of KBr studied by extended x-ray-absorption fine structure" Surf.Sci.(in press).

M.Kiguchi、T.Yokoyama、T.Tsuduki、S.Terada、Y.Kitajima 和 T.Ohta：“通过扩展 X 射线吸收精细结构研究 KCl 在 KBr 解理 (001) 面上的异质外延生长” Surf