STUDY OF REACTION DYNAMICS OF O(^1D) ATOM VIA THE COMPLETE ROVIBRATIONAL STATE DISTRIBUTION OF REACTION PRODUCTS

研究O（^1D）原子与简单分子反应的动力学是理解气相化学反应的基本原理所不可缺少的。本研究特别关注O(^1D) + N_2O反应。O（^1D）与N_2O的反应有两个产物通道(i) NO + NO和（ii） N_2 + O_2。通道(i)比通道（ii）具有更大的分支比，是平流层NO的主要来源。在激光光解N_2O生成O（^1D）原子后，通过激光诱导荧光检测，我们完全确定了该反应的NO（v= 0,1,2）产物的旋转态分布。在低压力和短泵探延迟时间的实验条件下，保证了无碰撞观察。研究发现，旋转分布的大部分与统计预测接近，但较高旋转水平j = 100的种群比统计分布的种群减少得更明显。更多n.观察到的旋转分布的统计趋势令人惊讶，因为没有非常稳定的中间体，而中间体往往能够长寿命地诱导有效的能量传递。此外，该反应的放热强度为340 kJ/mol，即使在通常为180 kJ/mol的O（^1D）反应中也是最大的。观察到的统计趋势与这种没有深势阱的大放热释放之间的关系是反应动力学中的一个重要问题。为了更深入地了解这一问题，我们在从头算势面上进行了准经典轨迹计算。结果表明，反应前半部分中间体的近统计能量分布和出口通道相互作用阻碍了产物的高旋转激发。我们已经获得了在射流膨胀和多光子电离光谱下探测N_2 + O_2通道的基本信息。少

To investigate the dynamics of reactions of O(^1D) atom with simple molecules is indispensable to understand gas-phase chemical reactions form the first principle. This study is especially focused on the O(^1D) + N_2O reaction. The reaction of O(^1D) with N_2O has two product channels(i) NO + NO and (ii) N_2 + O_2. The channel (i) have larger branching ratio than channel (ii) and this channlel is the major source of the stratospheric NO.We have fully determined the rotational state distribution of NO(v=0, 1, 2) products of this reaction via laser-induced fluorescence detection after the production of O(^1D) atom with laser photolysis of N_2O. Collision-free observation was ensured under experimental conditions of low pressure and short pump-probe delay time. It is found that the most part of the rotational distribution is close to the statistical prediction although the population in higher rotational levels j = 100 diminishes more significantly than that of the statistical distributio … More n. The observed statistical trend in the rotational distribution is surprising judging from the absence of very stable intermediates which often enable long lifetime inducing efficient energy transfer within the intermediates. Furthermore, the exothermicity of this reaction of 340 kJ/mol is the largest even among the exothermic O(^1D) reactions typically as large as 180 kJ/mol for OH production. The relation between the observed statistical trend and the release of such large exothermicity without deep potential well is an important question in the reaction dynamics. To obtain deeper insight in this issue, we performed quasi-classical trajectory calculation on an ab initio potential surface. It is suggested that the near-statistical energy distribution in the intermediate in the former half of the reaction and exit channel interaction prohibits the high rotational excitation of the product.We have obtained elementary information to detect the N_2 + O_2 channel under jet expansion and multi-photon ionization spectroscopy. Less