To support this assignment from the mass spectrum, we have calculated the equilibrium dissociation energy (D e ) for the reaction C 2+ 2 --→ 2 C + at the CCSD(T)/aug-cc-pVTZ level of theory. The obtained value of D e = -5.3 eV shows that this reaction is strongly exothermic, which means that C + is a more energetically favorable ion. The estimated lifetime of the metastable triplet C 2+ 2 into two C + ions is 0.9 ns (see ESI for details), which makes the detection of this species with MS impossible. Using aBOMD simulations of the fragmentation dynamics, we also observe peaks at the m/z region of interest (12 ≤ m/z ≤ 14), which all correspond to CH + x species (Figure ). The further fragmentation of CH +