Title: Stability of C₅₉ Knockout Fragments from Femtoseconds to Infinity

Authors: Michael Gatchell, Naemi Florin, Suvasthika Indrajith, José Eduardo Navarro Navarrete, Paul Martini, MingChao Ji, Peter Reinhed, Stefan Rosén, Ansgar Simonsson, Henrik Cederquist, Henning T. Schmidt, and Henning Zettergren

DOI: https://doi.org/10.3847/1538-4357/ad3930

Abstract: We have studied the stability of C₅₉ anions as a function of time, from their formation on femtosecond timescales to their stabilization on second timescales and beyond, using a combination of theory and experiments. The C₅₉^– fragments were produced in collisions between C₆₀ fullerene anions and neutral helium gas at a velocity of 90 km s⁻¹ (corresponding to a collision energy of 166 eV in the center-of-mass frame). The fragments were then stored in a cryogenic ion beam storage ring at the DESIREE facility, where they were followed for up to 1 minute. Classical molecular dynamics simulations were used to determine the reaction cross section and the excitation energy distributions of the products formed in these collisions. We find that about 15% of the C₅₉^– ions initially stored in the ring are intact after about 100 ms and that this population then remains intact indefinitely. This means that C 60 fullerenes exposed to energetic atoms and ions, such as stellar winds and shock waves, will produce stable, highly reactive products, like C₅₉, that are fed into interstellar chemical reaction networks.