Ab initio simulation of the effects of substitutional doping of oxygen in the semifullerene (C₃₀)

Using first principles calculations, we studied the effects of substitutionally doping a 30-atom semifullerene (C30) with oxygen atoms, within the Density Functional Theory (DFT) and the pseudopotential formalism. We analyzed two C30 structures, one with a pentagonal and one with a hexagonal base. In both cases, the substitutionally absorbed oxygen atoms break the bonds between pentagons and hexagons of the semifullerene. We show that each semifullerene breaks into two geometrically flat structures, one of them being consistent with a known ring isomer of the fullerene C20. We used the Quantum ESPRESSO package code and the generalized gradient corrected Perdew-Burke-Ernzerhof (PBE) approximation for the exchange and correlation functional. (paper)