Figure 5

(a) Comparison of predicted associate/penning branching ratio (see text) with experimental data from Perugia laboratory³². (b) Comparison of an exclusive concerted flip mechanism (see text) with data from Lausanne laboratory corrected for predissociation²⁴. In such panel, the role of the initial molecular orientation is emphasized; as in Fig. 4, marked red and black lines indicate the calculations performed in the case of collisions involving the ³P₂ and ³P₀ spin–orbit states of Ne^*, respectively. Lower panel: A schematic view of precursor state structures promoting reaction and associated ion formation. Note that while the half-filled p orbital of Ne^* atom exhibits a nodal plane, the HOMO orbital of N₂ from which the electron is removed, does not exhibit any nodal plane perpendicular to the bond axis and passing for its center of mass³³. Therefore, in the second and fourth cases, characterized by overlap null between orbitals exchanging the electron, the ionization by direct mechanism is forbidden and the reaction can occur only by indirect mechanism (see text).