Quantum-chemical calculation of carbododecahedron formation in carbon plasma

Abstract

The ground state of the molecule consisting of 10 carbon atoms in C10rg “ring” conformation and the energy of its metastable C10st “star” conformation are reported. The reaction coordinate for the isomeric transition C10st → C10rg was calculated using density functional theory (DFT) with UB3LYP/6-31G(d,p). It was established that a 5-fold symmetry axis is conserved in this isomeric transition. The total energy of the ring isomer is by 10.33 eV (9.16 eV as zero-point energy corrected) lower than that of the star isomer. The energy barrier for the transition from the metastable star state to the ring state is 2.87 eV (3.57 eV as zero-point energy corrected). An analysis of possible chemical reactions in carbon plasma involving C10st and C10rg and leading to the formation of C20 fullerenes was performed. It was revealed that the presence of the C10st conformation in the reaction medium is a necessary condition for C20 fullerene formation. It was shown that the presence of hydrogen atoms in carbon plasma and UV radiation accelerate the C10st → C10rg transition and thus suppress the C20 fullerene formation.