State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, China.
J Phys Chem A. 2011 Mar 10;115(9):1500-7. doi: 10.1021/jp109169f. Epub 2011 Jan 19.
The dissociation dynamics of HOD via two-photon excitation to the C̃ state have been investigated using the H-atom Rydberg tagging time-of-flight (TOF) technique. The H-atom action spectrum for the C̃ ← X̃ transition shows resolved rotational structure. Product translational energy distributions and angular distributions have also been recorded for the H + OD channel for three excited levels each with k(a)′ = 2. From these distributions, quantum state distributions and angular anisotropy parameters (β2 and β4) for the OD product were determined. These results are consistent with the nonadiabatic predissociation picture illustrated in the one-photon dissociation process for H2O. The heterogeneous dissociation pathway via Coriolis coupling is the dominant dissociation process in the present study. A high proportion of the total available energy is deposited into the rotational energy of the OD product. The anisotropic recoil distributions reveal the distinctive contributions from the alignment of the excited states and the dissociation process. Comparisons are also made between the results for HOD and H2O via the equivalent rotational transitions. The OH bond energy, D(o)(H−OD), of the HOD molecule is also determined to be 41283.0 ± 5 cm(-1).
通过双光子激发 C̃态研究了 HOD 的离解动力学，使用了 H 原子里德堡标记飞行时间（TOF）技术。C̃←X̃跃迁的 H 原子作用光谱显示出分辨的转动结构。还记录了 H + OD 通道的三个激发态的 H + OD 通道的产物平移能分布和角分布，每个激发态的 k(a)′=2。从这些分布中，确定了 OD 产物的量子态分布和角各向异性参数（β2 和β4）。这些结果与单光子离解过程中所示的非绝热预离解图一致，H2O。本研究中，通过科里奥利耦合的非均相离解途径是主要的离解过程。大量的可用能量沉积在 OD 产物的转动能中。各向异性的反冲分布揭示了激发态的取向和离解过程的独特贡献。还通过等效转动跃迁比较了 HOD 和 H2O 的结果。HOD 分子的 OH 键能 D(o)(H−OD)也被确定为 41283.0±5cm-1。
