Department of Physics and Astronomy and the Center for Simulational Physics, The University of Georgia, Athens, Georgia 30602, USA.
Department of Chemistry, Duke University, Durham, North Carolina 27708, USA.
Nat Commun. 2015 Mar 24;6:6629. doi: 10.1038/ncomms7629.
Accurate rate coefficients for molecular vibrational transitions due to collisions with H₂, critical for interpreting infrared astronomical observations, are lacking for most molecules. Quantum calculations are the primary source of such data, but reliable values that consider all internal degrees of freedom of the collision complex have only been reported for H₂-H₂ due to the difficulty of the computations. Here we present essentially exact, full-dimensional dynamics computations for rovibrational quenching of CO due to H₂ impact. Using a high-level six-dimensional potential surface, time-independent scattering calculations, within a full angular momentum coupling formulation, were performed for the de-excitation of vibrationally excited CO. Agreement with experimentally determined results confirms the accuracy of the potential and scattering computations, representing the largest of such calculations performed to date. This investigation advances computational quantum dynamical studies representing initial steps towards obtaining CO-H₂ rovibrational quenching data needed for astrophysical modelling.
由于与 H₂ 碰撞而导致分子振动跃迁的精确速率系数对于解释红外天文观测至关重要，但对于大多数分子来说，这些速率系数都缺乏。量子计算是此类数据的主要来源，但由于计算的难度，只有 H₂-H₂ 的碰撞复合物的所有内部自由度都得到了可靠的数值。在这里，我们提出了一种用于 CO 由于 H₂ 冲击而发生的振动态猝灭的基本精确的全维动力学计算方法。使用高水准的六维势能面，在全角动量耦合形式下进行了振动激发的 CO 的退激发的时间独立散射计算。与实验确定的结果一致，证明了势能和散射计算的准确性，这是迄今为止进行的此类计算中规模最大的一次。这项研究推进了计算量子动力学研究，为获得天体物理模型所需的 CO-H₂ 振动态猝灭数据迈出了最初的一步。
