Fourier-Transform Raman and Infrared Spectroscopy

傅里叶变换-拉曼光谱实验已被引入几个实验室，供化学和生物化学专业的学生以及其他高级理科学生使用。更高的分辨率（约0.1 cm-l）和近红外范围的新ft -拉曼仪器允许更复杂的实验。在生物化学实验室，学生们在一个新的实验中使用拉曼光谱来研究分散在水中的合成磷脂双层。学生将通过观察CH和CC拉伸区域的强度，监测双棕榈酰磷脂酰氯双层内部碳氢链从有序到无序结构的变化作为温度的函数。研究了胆固醇作为添加剂的作用，使学生更多地了解细胞膜的结构。在分析化学实验室中，学生使用拉曼光谱法用内标法研究标准二甲苯混合物的组成。他们还将比较拉曼光谱和红外光谱取样的难易程度。对于物理化学实验室，将扩大红外光谱分析振动旋转带的范围。作为分析HCl中两个氯同位素在气相振动-旋转吸收带中的旋转结构的经典实验的替代，现在学生可以对HBr中的溴同位素进行类似的实验。改进的近红外能力有助于研究HCl或HBr光谱中的泛音，从而绘制势阱的下部，并发现键长随振动激发的变化情况。对于高级分析和物理实验室的学生来说，一项比较1,2-二氯乙烯顺式和反式异构体的拉曼和红外光谱的新实验提供了用于分配每种异构体的所有12种振动基本原理的数据。新仪器的红外和拉曼特性都支持本科生的研究。该仪器为学生提供了更广泛、更深入地了解振动光谱学理论和应用的机会。

Fourier transform-Raman spectroscopic experiments are being introduced into several laboratories for chemistry and biochemistry majors and other upper-level science students. The higher resolution (about 0.1 cm-l) and near-infrared range of the new FT-Raman instrument permit more sophisticated experiments. For the biochemistry laboratory, students use Raman spectroscopy in a new experiment to study synthetic phospholipid bilayers dispersed in water. Students will monitor the change from ordered to disordered structure in the hydrocarbon chains in the interior of dipalmitoylphosphatidylchloine bilayers as a function of temperature by observing intensities in the CH and CC stretching regions. The effect of cholesterol as an additive is studied allowing students learn more about the structure of cell membranes. In the analytical chemistry laboratory students use Raman spectroscopy to study the composition of a standard xylenes mixture using the method of internal standards. They will also compare the ease of sampling for Raman and infrared spectroscopies. For the physical chemistry laboratory, the scope of analyzing vibration-rotation bands by infrared spectroscopy will be extended. As an alternative to the classic experiment of analyzing the rotational structure due to the two chlorine isotopes in HCl in the gas-phase vibration-rotation absorption band, it is now possible for students to do a similar experiment on the bromine isotopes in HBr. The improved near-infrared capability facilitates the study of overtones in the HCl or HBr spectrum and thus mapping the lower part of the potential well and finding how the bond length varies with vibrational excitation. For students in the advanced analytical and physical laboratory, a new experiment comparing the Raman and infrared spectra of the cis and trans isomers of 1,2-dichloroethylene provides data used to assign all twelve of the vibrational fundamentals of each of the isomers. Both the infrared and Raman features of the new instrument support und ergraduate student research. This instrumentation provides opportunities for students to have a broader, deeper understanding of the theory and application of vibrational spectroscopy.