Rate coefficients for rotational state-to-state transitions in H 2 O + H 2 O collisions for cometary and planetary applications, as predicted by mixed quantum-classical theory
Rate coefficients for rotational state-to-state transitions in H 2 O + H 2 O collisions for cometary and planetary applications, as predicted by mixed quantum-classical theory
复制标题
混合量子经典理论预测的彗星和行星应用中 H 2 O H 2 O 碰撞中旋转态到态跃迁的速率系数
DOI：
10.1051/0004-6361/202245699
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发表时间：
2023
影响因子：
6.5
通讯作者：
Babikov, Dmitri
中科院分区：
文献类型：
--
作者：
Mandal, Bikramaditya;Babikov, Dmitri
我们提出了一种新的计算H2O + H2O体系中旋转态之间状态到状态转换的碰撞截面的方法，用于生成一个新的碰撞速率系数数据库，用于彗星和行星的应用。方法使用混合量子-经典理论方法进行计算，该方法在代码MQCT中实现。在这些计算中使用的旋转态的大基集使我们能够在很宽的温度范围内预测对位和邻位水的441种转变的热平均截面。结果H2O + H2O体系中所有的态到态跃迁都分裂成两个明确的组，其中一组具有较高的横截面值和较低的能量转移，对应于偶极子-偶极子驱动过程。另一类具有更小的横截面和更高的能量转移，由高阶相互作用项驱动。我们对理论误差条进行了详细的分析，并对状态到状态的转变矩阵进行了对称化，以确保每个转变的激发和猝灭过程都满足微观可逆性原则。我们还将我们的结果与文献中关于H2O + H2O碰撞的其他数据进行了比较。
AimsWe present new calculations of collision cross sections for state-to-state transitions between the rotational states in an H2O + H2O system, which are used to generate a new database of collisional rate coefficients for cometary and planetary applications.MethodsCalculations were carried out using a mixed quantum-classical theory approach that is implemented in the code MQCT. The large basis set of rotational states used in these calculations permits us to predict thermally averaged cross sections for 441 transitions in para- and ortho-H2O in a broad range of temperatures.ResultsIt is found that all state-to-state transitions in the H2O + H2O system split into two well-defined groups, one with higher cross-section values and lower energy transfer, which corresponds to the dipole-dipole driven processes. The other group has smaller cross sections and higher energy transfer, driven by higher-order interaction terms. We present a detailed analysis of the theoretical error bars, and we symmetrized the state-to-state transition matrixes to ensure that excitation and quenching processes for each transition satisfy the principle of microscopic reversibility. We also compare our results with other data available from the literature for H2O + H2O collisions.