CRIF:ID-Design and Construction of a 1 to 10 GHz Pulsed-beam, Fourier-Transform Spectrometer

美国亚利桑那大学的Stephen Kukolich教授获得化学研究仪器和设施仪器开发项目的这一奖项后，将开发一种脉冲波束傅里叶变换微波光谱仪，用于测量过渡金属配合物、氢键配合物和其他分子在微波光谱1至10 GHz区域的旋转转变频率。与以前的脉冲束FT微波光谱仪不同，这将允许测量低于4 GHz的频率，这对大分子非常重要。大分子从高旋转激发态（高J态）产生的跃迁具有复杂的旋转光谱，使这种光谱难以分配。大分子的旋转冷态（低J态）的转变简化了，也不那么拥挤了，但是这种转变的获取受到限制，因为其中一些转变落在技术上难以接近的4 GHz以下的光谱区域。所提出的仪器将能够进入该区域，从而能够分配旋转光谱和确定大分子的分子几何形状。该光谱仪将实现以下结构和四极耦合测量：1)双核过渡金属配合物，2)选择用于模拟生物系统中相互作用（如碱基对识别和蛋白质折叠）的较大氢键配合物，3)具有较大配体的过渡金属配合物，以及4)其他生物感兴趣的分子。拟议的研究项目将在亚利桑那大学研究生和本科生的合作和参与下进行。参与研究项目将使学生获得化学、量子力学、计算机技术、微波电子学、光谱学和物理测量等基础知识和经验。

With this award from the Chemistry Research Instrumentation and Facilities Instrument Development program, Professor Stephen Kukolich of the University of Arizona will develop a pulsed-beam, Fourier-transform microwave spectrometer to measure rotational transition frequencies for transition metal complexes, hydrogen-bonded complexes, and other molecules in the 1 to 10 GHz region of the microwave spectrum. Unlike previous pulsed-beam FT microwave spectrometers, this will allow measurement of frequencies below 4 GHz, which is very important for large molecules. Large molecules have complicated rotational spectra for transitions originating from high rotationally excited states (high J states), making such spectra difficult to assign. Transitions from rotationally cold states (low J states) of large molecules are simplified and less congested, but access to such transitions has been limited, since some of these transitions fall in the technologically inaccessible spectral region below 4 GHz. The proposed instrument would be able to access this region, and thus enable assignment of rotational spectra and determination of molecular geometries of large molecules.The spectrometer will enable structure and quadrupole coupling measurements for: 1) dinuclear transition metal complexes, 2) larger hydrogen bonded complexes chosen to model interactions in biological systems, such as base-pair recognition and protein folding, 3) transition metal complexes with larger ligands, and 4) other molecules of biological interest. The proposed research projects will be carried out with collaboration and participation of graduate and undergraduate students at The University of Arizona. Participation in the research projects will allow the students to gain experience and knowledge in the fundamentals of chemistry, quantum mechanics, computer technology, microwave electronics, spectroscopy, and making physical measurements.