Brunsvold Amy L, Upadhyaya Hari P, Zhang Jianming, Cooper Russell, Minton Timothy K, Braunstein Matthew, Duff James W
J Phys Chem A. 2008 Mar 20;112(11):2192-205. doi: 10.1021/jp710025v.
The dynamics of O(3P) + CO collisions at a hyperthermal collision energy near 80 kcal mol-1 have been studied with a crossed molecular beams experiment and with quasi-classical trajectory calculations on computed potential energy surfaces. In the experiment, a rotatable mass spectrometer detector was used to monitor inelastically and reactively scattered products as a function of velocity and scattering angle. From these data, center-of-mass (c.m.) translational energy and angular distributions were derived for the inelastic and reactive channels. Isotopically labeled C18O was used to distinguish the reactive channel (16O + C18O 16OC + 18O) from the inelastic channel (16O + C18O 16O + C18O). The reactive 16OC molecules scattered predominantly in the forward direction, i.e., in the same direction as the velocity vector of the reagent O atoms in the c.m. frame. The c.m. translational energy distribution of the reactively scattered 16OC and 18O was very broad, indicating that 16OC is formed with a wide range of internal energies, with an average internal excitation of approximately 40% of the available energy. The c.m. translational energy distribution of the inelastically scattered C18O and 16O products indicated that an average of 15% of the collision energy went into internal excitation of C18O, although a small fraction of the collisions transferred nearly all the collision energy into internal excitation of C18O. The theoretical calculations, which extend previously published results on this system, predict c.m. translational energy and angular distributions that are in near quantitative agreement with the experimentally derived distributions. The theoretical calculations, thus validated by the experimental results, have been used to derive internal state distributions of scattered CO products and to probe in detail the interactions that lead to the observed dynamical behavior.
利用交叉分子束实验以及在计算得到的势能面上进行的准经典轨迹计算，研究了碰撞能量接近80千卡/摩尔的超热条件下O(3P) + CO碰撞的动力学过程。在实验中，使用了一个可旋转的质谱仪探测器来监测非弹性散射和反应性散射产物随速度和散射角的变化。根据这些数据，得出了非弹性和反应性通道的质心平动能量和角分布。使用同位素标记的C18O来区分反应性通道（16O + C18O→16OC + 18O）和非弹性通道（16O + C18O→16O + C18O）。反应性的16OC分子主要向前散射，即在质心系中与试剂O原子的速度矢量方向相同。反应性散射的16OC和18O的质心平动能量分布非常宽，这表明16OC是在很宽的内能范围内形成的，平均内部激发约为可用能量的40%。非弹性散射的C18O和16O产物的质心平动能量分布表明，平均15%的碰撞能量进入了C18O的内部激发，尽管一小部分碰撞将几乎所有的碰撞能量都转移到了C18O的内部激发上。理论计算扩展了此前关于该体系已发表的结果，预测的质心平动能量和角分布与实验得出的分布几乎在定量上一致。经实验结果验证的理论计算已被用于推导散射CO产物的内部态分布，并详细探究导致观察到的动力学行为的相互作用。
