Before the theoretical differential cross section can be calculated, the covalent potential of NaI has to be determined first. The ionic potential is said to be well-known. The actual covalent potential is a result, generated in the interpretation of the experimental results. In the original text, the potential parameters have been summarized in a table as well, and Acov,
H12 and Hrot are said to be derived from the present work. So the covalent potential is determined using the experimental results, the deflection function is determined using the potential and the theoretical differential cross section is determined using the deflection function.
In this module we aim for an exact expression of the potential and the deflection function, not yet for the differential cross section. Especially the potential may be of interest separately. The results of this module will also be used as input in A08-m5bii, where the theoretical differential cross section will be calculated.
The potential curves (including the parameters) and deflection functions that are determined here can be seen as `theoretical results'. As such, they are copied to the Results module A08-m4bii1. They could also be provided in some other way with an extra label that permits interested readers to locate them.
In this module we concentrate on determining the potential parameters and H12. We have separated the determination of these parameters from the calculation of the differential cross section for two reasons:
In theory, the potential has to be known in order to calculate the cross section;
In practice, the interpretation module is large and complicated, so that it is important to provide it with an explicit structure, for the sake of clarity.
Therefore we try to enhance the information network by making explicit additional modular structure.
Separating the determination of the potential parameters and the cross section nevertheless poses a problem. The calculation did not take place linearly (following the steps of the determination of the potential, the subsequent deflection function and the subsequent calculation of the cross section), but in an entangled fitting process. In the original version of the article, a section was dedicated to the comparison of the calculations and the measurements. During this comparison some potential parameters were obtained. The discrepancies identified in this section were summarized and then discussed in the next section called 7.Discussion.
The distinction of a module about the parameters, separate from the module about the cross section, implies that the comparison between the calculations and measurements that does not directly lead to the determination of a parameter takes place in module A08-m5bii about the cross section.