STUDY OF REACTION DYNAMICS VIA MEASUREMENTS OF DIFFERENTIAL CROSS SECTIONS DEPENDENT ON ROTATIONAL ANGULAR MOMENTUM POLARIZATION OF REACTION PRODUCTS

通过测量取决于反应产物的旋转角动量极化的微分截面来研究反应动力学

基本信息

批准号：
11640506
负责人：
FUJIMURA Yo
金额：
$ 1.86万
依托单位：
KYOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

项目摘要

Chemical dynamics of elementary gas phase reactions have been studied via Doppler-resolved polarization spectroscopy. By using this technique, differential cross sections can be measured state-resolved manner. Furthermore, this method enables us to measure the polarization of the rotational angular momentum of reaction products.Collision-free diatomic product molecules were probed with high-resolution dye laser excitation and its Doppler-broadened line profiles were analyzed to extract the information of vector properties such as differential cross sections and rotational angular momentum polarization. We investigated the reactions of O(^1D) or O(^3P) atom with some several simple molecules. The followings are the summaries of this study. 1) For O(^1D)+N_2O→NO+NO reaction, the rotational angular momentum of the NO products are isotropic and consistent with the efficient energy randomization within all the degrees of freedom of reaction intermediates leading to apparent statistical rovi … More brational state distribution of NO products despite the absence of a deep potential well. 2) For O(^3P)+RH→OH+R reaction (RH : saturated hydrocarbons), reaction mechanism varies with collision energy and traditional understanding of a simple rebound abstraction mechanism is not universally proper especially in high collision energy. 3) For O(^1D)+RH→OH+R reaction, the suggested two-type mechanisms dependent on the size of RH and rovibrational state of OH products are not largely different in the lifetime of reactive intermediate. Rotational angular momentum vectors of high rotational levels are perpendicular to the scattering plane, that is, C-O-H bending motion exerts the OH rotation. This trend is similar to the O(^1D)+H_2O reaction, where O(^1D) insertion is dominant as in the O(^1D)+RH reaction.To obtain these finding is only enabled by polarization Doppler method. Some of the findings in this study give new understandings Which are opposite to the previous ones based on insufficient state-resolved measurements. The study elucidating elementary bimolecular reactions in this manner is essential for the fundamental understanding of chemical reaction dynamics. Less

通过多普勒分辨偏振光谱研究了基本气相反应的化学动力学，通过使用该技术，可以以状态分辨的方式测量微分截面，此外，该方法使我们能够测量反应的旋转角动量的偏振。利用高分辨率染料激光激发探测无碰撞双原子产物分子，并分析其多普勒展宽谱线轮廓，以提取矢量特性信息，例如微分截面和旋转角我们研究了 O(^1D) 或 O(^3P) 原子与一些简单分子的反应，以下是本研究的摘要 1) 对于 O(^1D)+N_2O→NO+NO 反应。，NO产物的旋转角动量是各向同性的，并且与反应中间体的所有自由度内的能量随机化一致有效，导致明显的统计拉维……更多NO产物的自由态分布，尽管不存在2）对于O(^3P)+RH→OH+R反应（RH：饱和烃），反应机制随碰撞能量的变化而变化，传统的简单回弹抽象机制的理解并不普遍适用，尤其是在高碰撞能量下。 3) 对于 O(^1D)+RH→OH+R 反应，取决于 RH 大小和 OH 产物的振动状态的两种机制在旋转角动量的寿命上没有很大差异。高旋转能级的向量垂直于散射平面，即 C-O-H 弯曲运动产生 OH 旋转，这种趋势类似于 O(^1D)+H_2O 反应，其中 O(^1D) 插入占主导地位，如O(^1D)+RH反应。要获得这些发现只能通过偏振多普勒方法才能实现，本研究中的一些发现给出了与之前基于不足的相反的新理解。以这种方式阐明基本双分子反应的研究对于化学反应动力学的基本理解至关重要。