论文标题
分子碰撞中的Rovbritation Transition速率的有效计算方法
Efficient computational methods for rovibrational transition rates in molecular collisions
论文作者
论文摘要
在不在局部热平衡中的环境中过程的天体物理模型需要了解分子碰撞中旋转型转变的状态对状态速率系数。但是，这些速率系数可以从耦合通道（CC）量子散射计算中获得，这些计算非常苛刻。在这里，我们提出了基于耦合态近似（CSA）的各种近似值，但更有效的方法，该方法忽略了人体固定坐标中的散射hamiltonian中的非对基形成型科里奥利偶联。特别是，我们研究了一种称为NNCC（最近的邻居科里奥利偶联）的方法[D. Yang，X。Hu，D。H. Zhang和D. Xie，J。Chem。物理。 148，084101（2018）]，包括科里奥利耦合到一阶。 NNCC方法比常见的CSA方法更高，但比完整的CC计算更有效，并且比CSA更准确。所有这些都通过显示状态到国家的横截面和汇率系数的汇率系数，并通过与He Atoms发生碰撞在Co $ _2 $中诱导的速率系数。还表明，可以通过将NNCC方法与我们在上一篇论文中完整的CC计算中应用的多通道扭曲波生近似（MC-DWBA）相结合，从而获得了CPU时间的进一步降低，实际上实际上不会损失准确性。
Astrophysical modeling of processes in environments that are not in local thermal equilibrium requires the knowledge of state-to-state rate coefficients of rovibrational transitions in molecular collisions. These rate coefficients can be obtained from coupled-channel (CC) quantum scattering calculations which are very demanding, however. Here we present various approximate, but more efficient methods based on the coupled-states approximation (CSA) which neglects the off-diagonal Coriolis coupling in the scattering Hamiltonian in body-fixed coordinates. In particular, we investigated a method called NNCC (nearest-neighbor Coriolis coupling) [D. Yang, X. Hu, D. H. Zhang, and D. Xie, J. Chem. Phys. 148, 084101 (2018)] that includes Coriolis coupling to first order. The NNCC method is more demanding than the common CSA method, but still much more efficient than full CC calculations, and it is substantially more accurate than CSA. All of this is illustrated by showing state-to-state cross sections and rate coefficients of rovibrational transitions induced in CO$_2$ by collisions with He atoms. It is also shown that a further reduction of CPU time, practically without loss of accuracy, can be obtained by combining the NNCC method with the multi-channel distorted-wave Born approximation (MC-DWBA) that we applied in full CC calculations in a previous paper.
