High Resolution Vibration - Rotation - Tunneling Spectroscopy of Weakly Bound Complexes

在这个项目中的物理化学程序的化学 司，Prof. Geoffrey A.加州生物医学研究所的布莱克 技术将从事详细的光谱研究， 分子间的力，如弱结合所揭示的，即，货车德瓦耳斯 和氢键的复合物。 这些研究将包括 实验、计算和理论研究。 的 复合物在组分气体的超声膨胀中形成， 高真空，研究将集中在远红外区域 其中大部分的分子间振动频率 复合体位于。 混合激光光谱仪， 在整个微波、毫米波和远红外区域， 用于获得光谱，分辨率适合于分辨 旋转，隧道，和超精细结构的振动 乐队. 实验工作与计算和 从理论研究中提取可靠的实验数据 分子间势能面 待调查的系统 包括由单体组成二阶、三阶和更高阶络合物 分子，如苯-水、氨-水、氮-水，和 一氧化碳-水;氩-水，其中几个氩原子和 几个水分子形成复合物;由水组成的二聚体复合物 氟化氢、氯化氢、氰化氢， 乙炔;和较大尺寸的络合物，如甘氨酸-水和其他的 生物学上的重要性，如涉及氨基酸和 嘌呤/嘧啶。 分子间力的精确描述在分子力学中起着至关重要的作用。 化学和分子生物学。 尽管长期以来， 弱，即，货车范德华力，特别是氢键， 相互作用缺乏可靠的定量数据， 描述这些影响。 获取信息的传统方法 分子间相互作用的基础上确定的 气体状态方程的维里展开系数， 谱线的压力展宽和其他经典性质。 最近的分子束散射实验已经产生了有用的 结果 分子束技术与高分子束技术的耦合 分辨率微波和激光光谱学提供了工具， 这意味着最详细和准确的数据弱约束 由两个或多个单独强结合的单体组成的复合物 分子得到。 本项目所进行的调查将 提供精确的结构、寿命和其他动力学参数 弱结合的分子复合物以及详细的定量 分子间势能的信息。 这些信息 不仅能更好地理解物质的凝聚力 一般来说，而且对于那些具有实际重要性的系统， 环境和生物化学。

In this project in the Physical Chemistry program of the Chemistry Division, Prof. Geoffrey A. Blake of the California Institute of Technology will engage in detailed spectroscopic studies of intermolecular forces as revealed by weakly bound, i.e., van der Waals and hydrogen-bonded, complexes. These studies will encompass experimental, computational, and theoretical investigations. The complexes are formed in supersonic expansions of the component gases into a high vacuum, and the studies will focus on the far infrared region where most of the telltale intermolecular vibrational frequencies of the complexes are located. Hybrid laser spectrometers that operate throughout the microwave, millimeter, and far-infrared regions will be used to obtain the spectra, with resolution appropriate to resolve the rotational, tunneling, and hyperfine structures of the vibrational bands. The experimental efforts are coupled to computational and theoretical studies to extract from the experimental data reliable intermolecular potential energy surfaces. Systems to be investigated include bi-, tri, and higher-order complexes composed of monomer molecules, such as benzene-water, ammonia-water, nitrogen-water, and carbon monoxide-water; argon-water in which the several argon atoms and several water molecules form a complex; dimer complexes composed of water with hygrogen fluoride, hydrogen chloride, hydrogen cyanide, and acetylene; and larger size complexes such as glycine-water and others of biological importance such as those involving amino acids and purines/pyrimidenes. Accurate descriptions of intermolecular forces play a pivotal role in chemistry and molecular biology. Despite long term interests in the weak, i.e., van der Waals and, in particular, hydrogen-bonded, interactions there is a paucity of reliable quantitative data that describe these effects. Traditional methods for obtaining information on the intermolecular interactions were based on the determination of the coefficients in the virial expansion of the equation of state of a gas, pressure broadening of spectral lines, and other classical properties. More recently molecular beam scattering experiments have yielded useful results. The couplings of molecular beam techniques with those of high resolution microwave and laser spectroscopies have provided tools by means of which the most detailed and exact data on weakly bound complexes composed of two or more individually strongly bound monomer molecules are obtained. The investigations pursued in this project will contribute accurate structures, lifetimes and other dynamical parameters of weakly bound molecular complexes as well as detailed quantitative information on their intermolecular potential energies. This information will lead not only to a better understanding about the cohesion of matter in general, but also for those systems that are of practical importance in environmental and biological chemistry.