Numerical Regge pole analysis of resonance structures in state-to-state reactive differential cross sections

This is the third (and the last) code in a collection of three programs [Sokolovski et al. (2011), Akhmatskaya et al. (2014)] dedicated to the analysis of numerical data, obtained in an accurate simulation of an atom-diatom chemical reaction. Our purpose is to provide a detailed description of a FORTRAN code for complex angular momentum (CAM) analysis of the resonance effects in reactive angular scattering [for CAM analysis of integral reactive cross sections see [Akhmatskaya et al. (2014)]. The code evaluates the contributions of a Regge trajectory (or trajectories) to a differential cross section in a specified range of energies. The contribution is computed with the help of the methods described in [Dobbyn et al. (1999), Sokolovski and Msezane (2004), Sokolovski et al. (2007)]. Regge pole positions and residues are obtained by analytically continuing S-matrix element, calculated numerically for the physical integer values of the total angular momentum, into the complex angular momentum plane using the PADE_II program [Sokolovski et al. (2011)]. The code represents a reactive scattering amplitude as a sum of the components corresponding to a rapid “direct” exchange of the atom, and the various scenarios in which the reactants form long-lived intermediate complexes, able to complete several rotations before breaking up into products. The package has been successfully tested on the representative models, as well as the F + H2→ HF+H benchmark reaction. Several detailed examples are given in the text.

本项研究为三部程序集（Sokolovski 等人，2011年；Akhmatskaya 等人，2014年）中的第三部（亦即最后一部），该程序集旨在对数值数据进行分析，这些数据通过精确模拟原子-双原子化学反应获得。我们的目标是提供对一种用于复杂角动量（CAM）分析反应性角散射共振效应的 FORTRAN 代码的详细描述（关于积分反应截面中的 CAM 分析，请参阅 Akhmatskaya 等人，2014年）。该代码评估了 Regge 轨迹（或轨迹）在指定能量范围内的微分截面贡献。贡献的计算得益于 Dobbyn 等人（1999年）、Sokolovski 和 Msezane（2004年）、Sokolovski 等人（2007年）所描述的方法。通过将数值计算的物理整数总角动量下的 S 矩阵元通过 PADE_II 程序（Sokolovski 等人，2011年）解析地延伸至复角动量平面，获得了 Regge 极点位置和留数。该代码将反应散射振幅表示为对应于原子快速“直接”交换的分量之和，以及各种反应物形成能够完成数个旋转后才分解为产物的长寿命中间复合物的情景。该软件包已在代表性模型以及 F + H2→ HF+H 基准反应上进行了成功测试。文中给出了几个详细的示例。