Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (UMR 8112 du CNRS), Observatoire de Paris-Meudon, Université Pierre et Marie Curie, Meudon Cedex 92195, France.
J Chem Phys. 2010 Jan 28;132(4):044313. doi: 10.1063/1.3297893.
The effect of nonadiabatic couplings on the collisional removal of O(2)(b (1)Sigma(g) (+),v) by O(2)(X (3)Sigma(g) (-), v=0) is investigated. Two-dimensional adiabatic and quasidiabatic potential energy surfaces for the excited dimer states and the corresponding nonadiabatic radial couplings have been computed by means of ab initio calculations. Alternately, a two-state theoretical model, based on the Landau-Zener and Rosen-Zener-Demkov assumptions, has been employed to derive analytical forms for the nonadiabatic couplings and an adiabatic-to-diabatic transformation only depending on a reduced set of adiabatic energy terms. Compared to the ab initio results, the predictions of the model are found to be highly accurate. Quantum dynamics calculations for the removal of the first ten vibrational states of O(2)(b (1)Sigma(g) (+),v) indicate a clear dominant contribution of the vibration-electronic relaxation mechanism relative to the vibration-translation energy transfer. Although the present reduced-dimensionality model precludes any quantitative comparison with experiments, it is found that the removal probabilities for v=1-3 are qualitatively consistent with the experimental observations, once the vibrational structure of the fragments is corrected with spectroscopical terms. Besides, the model served to show how the computation of the adiabatic PESs just at the crossing seam was sufficient to describe the nonadiabatic dynamics related to a given geometrical arrangement. This implies considerable savings in the calculations which will eventually allow for larger accuracy in the ab initio calculations as well as higher dimensional treatments.
非绝热耦合对 O(2)(b (1)Σ(g) (+),v) 通过 O(2)(X (3)Σ(g) (-), v=0) 碰撞去除的影响进行了研究。通过从头计算计算了激发二聚体态的二维绝热和准绝热势能面以及相应的非绝热径向耦合。或者，基于 Landau-Zener 和 Rosen-Zener-Demkov 假设的两态理论模型被用来推导出非绝热耦合的解析形式和仅依赖于一组简化绝热能量项的绝热-非绝热变换。与从头计算结果相比，该模型的预测被发现非常准确。对 O(2)(b (1)Σ(g) (+),v) 的前十个振动态的去除的量子动力学计算表明，相对于振动-平移能量转移，振动-电子弛豫机制的贡献明显占主导地位。尽管目前的降维模型排除了与实验的任何定量比较，但发现一旦用光谱术语修正碎片的振动结构，v=1-3 的去除概率与实验观察定性一致。此外，该模型表明，仅在交叉缝处计算绝热 PES 就足以描述与给定几何排列相关的非绝热动力学。这意味着计算上的显著节省，最终将允许更高的准确性在从头计算以及更高维的处理。
