Competition between different mechanisms of stability loss for the (C20)2 cluster dimer

The thermal stability of the (C-20)(2) cluster dimer consisting of two C-20 fullerenes has been numerically examined using the tight-binding method. The simulation of the dynamics of the (C-20)(2) dimer at temperatures of T = 2000-3500 K shows that the finite lifetime tau of this metastable system is determined by two fundamentally different processes: the decay of one of the C-20 fullerenes and the coalescence of two C-20 fullerenes to the C-40 cluster. The activation energies for these processes. E-a approximate to 3.4 and 2.7 eV, respectively, as well as their frequency factors, have been determined by analyzing the tau(T) dependence.