In this thesis, results from Mutual Neutralization experiment carried out atthe DESIREE facility, involving merged interacting ion beams, of oppositelycharged C60 ions are presented. This reaction may be of importance for explain-ing reliable estimates of the ionization balance in astrophysical environments,which defines the chemistry in molecular gas clouds. To interpret the resultsfrom the experiment, and for estimating the reaction cross section as a functionof collision energy, the Landau-Zener model is employed, with the electronicexcited states of neutral C60 calculated using Time-Dependent Density Func-tional Theory. The importance of applying an interacting potential that takesinto account mutual polarization effects and the finite sizes of the collisionpartners, in the Landau-Zener model is highlighted. We find that the total MNcross section is similar for different coupling elements. A good agreement isobserved between the Landau-Zener model and the experiment, and the modelis applied to calculate the total Mutual Neutralization cross section as a functionof center-of-mass collision energy, for a range of (0.0 - 4.98) eV excitationenergy. We find the cross section is almost an order of magnitude larger thanwhat has been reported for H+ + H− collisions and comparable with modelresults for C+60 + e− → C60 reactions. Thus, it suggests that Mutual Neutraliza-tion processes indeed may be important for the charge balance in interstellarmolecular clouds where electrons are not the main carriers of negative charges.©Raka Paul, Stockholm 2023Distributor: Department of Physics, Stockholm University