MEASUREMENTS OF STATE-RESOLVED DIFFERENTIAL CROSS SECTIONS VIA HIGH-RESOLUTION POLARIZED DOPPLER SPECTROSCOPY

利用多普勒分辨偏振光谱研究了元素气相反应的化学反应动力学。利用该技术，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产物旋转角动量的极化。利用高分辨率染料激光探测无碰撞双原子产物分子，分析其多普勒-展宽谱线，提取其微分截面和旋转角动量极化等矢量性质信息。结果如下所示。1)对于H_2反应，反应概率的微分截面和碰撞能量依赖强烈依赖于产物OH分子的反振动态。与准经典轨迹计算的临界比较，在最近的最先进的ab - i- t上…更多的势能面。2)对于N_2O反应，在反应中间体的所有自由度内，有效的能量随机化导致产物NO分子的统计反振动态分布，尽管没有深势阱。这种行为通常被解释为分子间振动-能量再分配，重点是光（氢）原子效应。3)对于C_2H_4和C_2H_6反应，插入0原子形成醇型中间体后反应中间体结构变化的差异体现在产物OH分子旋转角动量极化的差异上。4)对于H_2O反应，主要反应途径是O原子插入H_2O的HO键，形成HOGH作为中间体。只有使用状态分辨偏振多普勒光谱才能得到这样的发现。此外，本研究的一些发现给出了与以往基于不充分的状态解析测量相反的新理解。以这种方式阐明基本双分子反应的研究对于基本理解化学反应动力学是必不可少的。少

Chemical reaction dynamics of elementary gas phase reactions have been studied via Dopplerresolved 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 reaction of O(^1D) atom with some several simple molecules. Following results are shown. 1) For H_2 reaction, differential cross sections and collision energy dependence of reaction probability strongly depend on ro-vibrational states of product OH molecules. Critical comparison with a quasi-classical trajectory calculation on a recent state-of-the-art ab init … More io potential energy surfaces. 2) For N_2O reaction, efficient energy randomization within all the degrees of freedom of reaction intermediates leads apparent statistical ro-vibrational state distribution of product NO molecules despite the absence of a deep potential well. Such a behavior is generally interpreted in terms of intermolecular vibrational-energy redistribution, with the emphasis of the light (hydrogen) atom effect. 3) For C_2H_4 and C_2H_6 reaction, the difference of the structural change of reactive intermediates after the insertion of 0 atom forming alcohol type intermediates is reflected in the difference of the polarization of rotational angular momentum of product OH molecules. 4) For H_2O reaction, the main reaction path is an insertion of O atom into HO bond of H_2O forming HOGH as an intermediate.To obtain such findings becomes possible only by the use of the state-resolved polarized Doppler spectroscopy. In addition, 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