X-ray Structural Analysis of the Monolayrs Adsorbed on Solid Surfaces

固体表面吸附单分子层的 X 射线结构分析

基本信息

批准号：
05453056
负责人：
INABA Akira
金额：
$ 4.74万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1993
资助国家：
日本
起止时间：
1993 至 1994
项目状态：
已结题

项目摘要

The momolayr of some simple molecules, which is physically adsorbed on a homogeneous surface of solids such as graphite, forms a two-dimensional molecular solid at low temperatures. We investigate the system by calorimetry, diffraction and neutron scattering. Such adsorbed monolayrs often exhibit phase transitions in the solid phase, which is similar to the case of the bulk solid. However, since the balance of the molecular interactions in this system is rather subtle, many phases appear depending upon the coverage and the temperature.The systems that we investigated were the monolayrs of isotopic methanes, neopentane, adamantane, sulfuryl fluoride, sulfur hexafluoride, camphor, tetrakis (methylthio) methane and others. All the molecules have globular shape and the orientational ordering at low temperatures is particularly interesting. The X-ray diffraction patterns were obtained for the monolayrs of adamantane, sulfur hexafluoride, camphor and tetrakis (methylthio) methane at ambient and low temperatures. The neutron diffraction patterns were also obtained for the monolayrs of fully-deuterated neopentane, fully-deuterated adamantane and sulfur hexafluoride at low temperatures.While the detailed structural analysis is now under way, the mechanism of the phase transitions seems to be of orientational order-disorder type. The nature of the phase transition of neopentane monolayr was investigated by inelastic and quasielastic neutron scattering. The dynamics in methane monolayrs were investigated by the rotational tunneling spectra observed by inelastic neutron scattering. Investigation of the dielectric properties of the monolayrs, which is our anotherproject, is now in progress by using hexagonal boron nitride as an adsorbent.

一些简单分子的摩尔分子，物理吸附在石墨等固体的均匀表面上，在低温下形成二维分子固体。我们通过量热法、衍射和中子散射来研究该系统。这种吸附的单分子层通常在固相中表现出相变，这与块状固体的情况类似。然而，由于该系统中分子相互作用的平衡相当微妙，因此根据覆盖范围和温度会出现许多相。我们研究的系统是同位素甲烷、新戊烷、金刚烷、硫酰氟、六氟化硫、樟脑的单层系统、四（甲硫基）甲烷等。所有分子都具有球形形状，并且低温下的取向排序特别有趣。在环境温度和低温下获得了金刚烷、六氟化硫、樟脑和四（甲硫）甲烷单层的 X 射线衍射图。还获得了全氘化新戊烷、全氘化金刚烷和六氟化硫单层在低温下的中子衍射图。虽然详细的结构分析正在进行中，但相变的机制似乎是定向有序的-紊乱类型。通过非弹性和准弹性中子散射研究了新戊烷单层相变的性质。通过非弹性中子散射观察到的旋转隧道光谱研究了甲烷单层的动力学。单层介电性能的研究是我们的另一个项目，目前正在进行使用六方氮化硼作为吸附剂。