Combined study of structural and thermodynamic investigations of monolayer adsorbed on graphite

本研究所涉及的体系是物理吸附在石墨表面的单分子膜。这项研究的目的是确定其二维结构，观察其动力学并研究其热力学性质。为了实现这一点，我们进行了X射线/中子衍射、中子散射、等温线和热容的测量。我们研究了下列分子的单分子膜：Ar、氪、氮、一氧化碳、一氧化二氮、甲烷(及其重氢类似物)、甲基氟化物、甲基氯、甲基溴、碘甲烷、新戊烷(及其重氢类似物)、四甲基锡、硫酰氟、六氟化硫、甲醇(及其重氢类似物)、叔丁醇和C&lt；我们还研究了一些混合物，发现了氪、氮、一氧化碳、甲烷、甲基氟化物、氯甲烷、新戊烷、硫酰氟和六氟化硫的单分子膜的二维相变。确定了一氧化碳、甲烷、甲基氟化物、新戊烷和甲醇单分子膜的二维结构。研究了分子的旋转态和振动态。研究了同位素甲烷和甲基氟化物的单分子膜的旋转隧道效应。新戊烷、硫酰氟化物和六氟化硫等球状分子的单分子膜存在取向无序相，这一研究证明了结构和热力学相结合对于揭示二维分子固体的性质是非常有效的。要系统地解决这一问题，国际合作是必不可少的，因为这个问题有很多方面需要研究。

The system which we dealt with in this study was the monolayer physically adsorbed on the surface of graphite. The purpose of the study was to determine the two-dimensional structure, to see the dynamics and to investigate the thermodynamic properties. In order to achieve this, X-ray/neutron diffraction, neutron scattering and measurements of the isotherm and the heat capacity were carried out.We investigated the monolayer of the following molecules ; argon, krypton, nitrogen, carbon monoxide, dinitrogen monoxide, methane (and its deuterated analogs), methyl fluoride, methyl chloride, methyl bromide, methyl iodide, neopentane (and its deuterated analog), tetramethyl tin, sulfuryl fluoride, sulfur hexafluoride, methanol (and its deuterated analogs), tert-butanol and C_<60>. Some mixtures were also investigated.We found some two-dimensional phase transitions for the monolayer of krypton, nitrogen, carbon monoxide, methane, methyl fluoride, methyl chloride, neopentane, sulfuryl fluoride and sulfur hexafluoride. The two-dimensional structure was determined for the monolayer of carbon monoxide, methane, methyl fluoride, neopentane and methanol. The rotational and vibrational states were also investigated. The rotational tunneling was investigated for the monolayer of isotopic methanes and methyl fluoride. An orientational disordered phase was found for the monolayer of some globular molecules such as neopentane, sulfuryl fluoride and sulfur hexafluoride.This study proved that the combination of the structural and thermodynamic investigations is quite effective to uncover the nature of the two-dimensional molecular solids. An international collaboration is essential to tackle with such problem systematically which has many aspect to be investigated.