Time-resolved appearance energies for fragment ions from C60

Time-resolved appearance energies (AEs) were determined for C58+ and C56+ by electron ionization of C60. Two methods were applied: (1) electron-space-charge trapping in the ion source of a tandem mass spectrometer and (2) Fourier transform mass spectrometry in an ion cyclotron resonance spectrometer. The AE for C58+ obtained in the limit of long ion trapping time at an evaporation temperature of 620 K is 44 ± 2 eV. This corresponds to a minimum intrinsic kinetic shift, IS = 30.4 eV due to radiative decay and agrees with recent results that cooling of C60 (and C60+) is dominated by black-body radiative decay below an internal temperature of 2300 K.