Analytical Application of Infrared Nonlinear Spectroscopy

该项目由分析和表面化学计划资助，涉及将非线性多共振四波混频（MFWM）光谱扩展到红外光谱范围内多个振动跃迁的选定激发。威斯康星大学麦迪逊分校的约翰·c·赖特教授和他的学生将使用多个红外激光器来瞄准分子内选定的跃迁，并诱导独特的激发响应，反射单个共振的和或差。该技术提供的无与伦比的选择性归功于与化学官能团相互作用相耦合的丰富的红外振动共振，以及使用四波混合方法消除基质，光谱和/或溶剂干扰的伴随能力。此外，固有的振动跃迁的清晰度将允许在室温下产生良好的分辨光谱。赖特教授还将这项技术扩展到红外指纹区域，这将允许对分析物分子结构进行更详细的评估。多共振四波混频非线性光谱学涉及使用多个红外激光器，以便明智地选择与复杂混合物中的特定成分、生物和聚合物大分子中的化学功能和/或有序系统中的构象差异相关的激发波长。该技术允许定性和定量化学区分，具有无与伦比的选择性。该项目得到了分析和表面化学计划的支持，其成功需要物理和分析光谱学家的跨学科努力，其成熟的发展将有利于先进材料和生物大分子的表征。

This project, supported in the Analytical and Surface Chemistry Program, involves the extension of nonlinear multiresonant four wave mixing (MFWM) spectroscopy to the selected excitation of multiple vibrational transitions in the infrared spectral range. Professor John C. Wright and his students at the University of Wisconsin at Madison will use multiple infrared lasers to target selected transitions within a molecule and induce unique excitation responses reflective of the sum or difference of individual resonances. The unparalleled selectivity afforded by this technique is attributed to the wealth of infrared vibrational resonances that are coupled to chemical functional group interactions, and the concomitant capability for elimination of matrix, spectral and/or solvent interferences using the four-wave mixing approach. In addition, the inherent sharpness of vibrational transitions will allow the generation of well resolved spectra at room temperatures. Professor Wright will also extend this technique to the fingerprint region of the infrared which will allow a more detailed assessment of analyte molecular structure. Multiresonant four wave mixing nonlinear spectroscopy involves the use of multiple infrared lasers to enable the judicious selection of excitation wavelengths related to specific components in complex mixtures, chemical functionalities in biological and polymeric macromolecules, and/or conformational distinctions in well ordered systems. This technique allows both qualitative and quantitative chemical differentiation with unparalleled selectivity. This project, supported in the Analytical and Surface Chemistry Program, is at a stage where its success will require the interdisciplinary efforts of physical and analytical spectroscopists, and its mature development will benefit the characterization of advanced materials and biomacromolecules.