Infrared Laser Spectroscopy

赖斯大学的Curl和Tittel将在化学学部实验物理化学项目中使用红外动力学光谱研究自由基的高分辨率红外光谱。利用单频连续波红外探测激光器，利用这些研究者先前开发的差频产生方案，获得了准分子激光光解制备的自由基的吸收红外光谱。研究的瞬态自由基包括C4H、HCCO（烯基）、HCCCO（丙基）和HCCCH（丙炔）。研究了一种观察超声速射流膨胀冷却自由基的高分辨率光谱的技术，并将其应用于分析CH2OH（羟甲基）中CO的拉伸振动。自由基是一种高活性的瞬态物质，在许多不同的化学反应中作为中间体产生。在这个研究项目中，瞬态自由基将被产生，它们对红外辐射的特征吸收，即它们的振动光谱，将被检查，以提供有关这些短寿命物种的结构和性质的信息。这些信息对这些重要反应中间体中化学键的基本性质有影响，并影响我们对燃烧反应和星际介质中的分子等不同领域的理解。

In this project in the Experimental Physical Chemistry Program of the Chemistry Division, Curl and Tittel of Rice University will investigate the high resolution infrared spectra of free radical species using infrared kinetic spectroscopy. The absorption infrared spectra of free radicals prepared using excimer laser photolysis is obtained using a single-frequency continuous-wave infrared probe laser by means of a difference frequency generation scheme developed previously by these investigators. Transient radicals to be studied include C4H, HCCO (ketenyl), HCCCO (propynonyl), and HCCCH (propargylene). A technique for observing the high resolution spectra of radicals cooled in a supersonic jet expansion will continue to be developed and applied to analyzing the CO stretching vibrations in CH2OH (hydroxymethyl). %%% Free radicals are highly reactive, transient species which are produced as intermediates in many different chemical reactions. In this research project transient free radicals will be produced, and their characteristic absorptions of infrared radiation, that is, their vibrational spectra, will be examined for the information they can provide on the structure and nature of these short-lived species. Such information has a bearing on the fundamental nature of chemical bonding in these important reaction intermediates and impacts our understanding of such diverse areas as combustion reactions and molecules in interstellar media.