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

本研究中所处理的体系是物理吸附在石墨表面的单分子层。该研究的目的是确定二维结构，观察动力学并研究热力学性质。为了实现这一点，进行了X射线/中子衍射，中子散射和测量的等温线和热容。氩、氪、氮、一氧化碳、一氧化二氮、甲烷（及其氘代类似物）、甲基氟、甲基氯、甲基溴、甲基碘、新戊烷（及其氘代类似物）、四甲基锡、硫酰氟、六氟化硫、甲醇（及其氘代类似物）、叔丁醇和C1 - 6烷基<60>。对氪、氮、一氧化碳、甲烷、氟甲烷、氯甲烷、新戊烷、硫酰氟和六氟化硫的单分子膜进行了二维相变研究。一氧化碳，甲烷，甲基氟，新戊烷和甲醇的单层的二维结构进行了测定。还研究了转动和振动态。研究了同位素甲烷和甲基氟单层膜的转动隧穿。在新戊烷、硫酰氟和六氟化硫等球形分子的单层膜中发现了取向无序相，证明了结构和热力学研究相结合是揭示二维分子固体本质的有效方法。要系统地解决这一问题，国际合作是必不可少的，这一问题有许多方面需要研究。

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.