This module Theoretical method is a compound module, containing two components: firstly the theoretical methods used to determine the states of the system and the transition probabilities between them, and secondly the methods for the calculation of the semiclassical differential cross section starting from those states and probabilities.
The different theoretical methods presented in this complex module are used at different stages of the problem-solving process. Therefore they were presented in different sections in the original article (3.Potential curves, the first half of 4.Calculations, 8.Rotational coupling), and therefore they are visited at different stages by the essay-type sequential path.
A result of the complexity of this module is that we have included this complex module in the essay-type path, in order to enhance the reader's understanding of the scientific discourse.
The `standard coupling' (associated to the Landau-Zener probability) is called the Landau-Zener coupling. That is an electronic coupling. In the original article the rotational coupling was presented as a refinement, when the model without rotational coupling turned out to be inadequate.
For the sake of clarity, this complex module is included in the essay-type sequential path, in spite of the fact that the information represented in this module is also represented in the constituent modules (i.e. in spite of the hierarchical overlap). The reason is, firstly, that the essay-type path through its constituent elementary modules is interrupted, as the path, after visiting A08-m3ci1 and A08-m3cii, first leads through part of the Interpretation module (see the Map of contents) before visiting the module A08-m3ci2 about the rotational coupling. Secondly, the module contains constituent modules at different levels.