Weak Complexes Studied by Fourier Transform Microwave Spectroscopy

在这个项目中，弱结合分子络合物的结构将用高分辨率傅里叶变换微波光谱来研究。该项目有六个组成部分：包含1)二氧化硫分子、2)水分子、3)环丙烷分子和4)稀有气体原子的二元络合物；5)由三个单体分子形成的络合物；6)高温研究。这些络合物将在组成气体和中性载气的高压混合物在超音速膨胀到真空中形成。通过这种膨胀，复合体也被冷却到非常低的平移和旋转温度，大约比绝对零度高出10度。这项工作将提供有关络合物的结构和内部运动(动力学)以及它们的电子性质(如电偶极矩)的信息。这些结果将提供关于分子间弱相互作用力的性质和分子间势函数的基本信息，并将有助于开发和测试模型和理论所需的数据库，这些模型和理论可以指导化学家和生化学家研究化合物如何相互作用并成长为更大的团簇。将被研究的团簇构成一种介于稀气和凝聚相之间的物质状态，在凝结和蒸发现象中起着至关重要的作用。弱分子间力在生物系统的结构和功能中也起着决定性的作用，在生物系统中，生物分子的一部分与其他部分相互作用，使其具有其功能的结构特征。这项研究中对分子间作用力的基础研究也将有助于为预测新的生化物质的理论提供测试和校准的数据基础。

In this project the structures of weakly bound molecular complexes are to be investigated by means of high resolution Fourier transform microwave spectroscopy. The project has six components: binary complexes containing 1) sulfur dioxide molecules, 2) water molecules, 3) cyclopropane molecules, and 4) rare gas atoms; 5) complexes formed by three monomer molecules; and 6) high temperature investigations. The complexes will be formed in the supersonic expansion into a vacuum of a high pressure mixture of component gases with a neutral carrier gas. Through this expansion the complexes are also cooled to very low translational and rotational temperatures, about 10 degrees above the absolute zero. The work will provide information on the structures and internal motions (dynamics) of the complexes, as well as on their electronic properties such as the electric dipole moment. The results will provide fundamental information about the nature of weak interaction forces between molecules and on intermolecular potential functions, and will contribute to the data base needed to develop and test models and theories which can guide chemists and biochemists in how compounds can interact and grow into larger clusters. %%% The clusters which will be studied constitute a state of matter that is intermediate between that of the dilute gas and the condensed phase and play a crucial role in condensation and evaporation phenomena. Weak intermolecular forces also play a decisive role in the structure and function of biological systems, in which parts of a biological molecule interact with other parts to give it a structure characteristic of its function. Fundamental investigations on intermolecular forces as conducted in this research will also contribute to the data base on which the theories for the prediction of new biochemical substances can be tested and calibrated.