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Theoretical methods=A08-m3c

The atom-atom model for ion-pair formation [Particulars on the model in a mesoscopic module (link type: 'is detailed in/wider range/project'; target: MESO-m3c-mod)] explains chemi-ionization in collisions via crossing of the diabatic potential energy surfaces of the system, or in other words, via a transition between two states of the system. A transition between two states can take place when the states are electronically coupled [Particulars on the transition (link type: 'contains/seggregated in/focused in'; target: A08-m3ci].

The atom-atom model for ion-pair formation takes into account the Landau-Zener transition probability between electronically coupled states of the same species [Focus on the LZ transition (link type: 'contains/segregated in/specialised in/is detailed in/focused in/essay-next'; target: A08-m3ci1]. The model can be further refined by also taking into account rotational coupling [Focus on the rotational coupling (link type: 'contains/segregated in/specialised in/is detailed in/focused in'; target: A08-m3ci2].

The differential cross section of chemi-ionization in sodium iodine collisions can be calculated via the potential curves of the system and the deflection function [More about the deflection function in a mesoscopic Theoretical methods module (link type: 'is detailed in/focused in/wider range/project'; target: MESO-m3c-defl]. For the semiclassical treatment of the cross section, the different contributions to the differential cross section are to be approximated. Here the stationary phase approximation, the uniform approximation and JWKB phase shifts are used [Particulars on these approximation in the Theoretical methods (link type: 'contains/segregated in/is detailed in/focused in': target: A08-m3cii)].