Stability of buckminsterfullerene, C60

We have measured delayed ionization of laser excited C-60 molecules by detection of ions in coincidence with emitted electrons. This makes it possible to distinguish ionization of C-60 from that of C-58 molecules created by the dominant process, emission of C-2. From the time dependence of the C-60(+) yield and the ratio of the yields of the two ions, we can determine both the dissociation energy, E-d = 10.8 +/- 0.3 eV, and the pre-exponential factor, A(d) similar to 3.4 x 10(21) s(-1) in the Arrhenius expression for the rate constant. The experiment has for the first time determined the power of photon emission from neutral C-60, which is an important competing process. The radiation may be represented by emission of 1 eV photons, with a rate k proportional to T-8 and with k = 10(5) s(-1) at T = 4000 K. (C) 2003 Elsevier B.V. All rights reserved.