Dimerization of Defect Fullerenes and the Orientational Phase Transition in Oxidized C-60 Fullerite

作者：Gutsev G L^*; Belay K G; Weatherford C A; Vasilets V N; Anokhin E M; Maksimychev A V; Val'ba O V; Martynenko V M; Baskakov S A; Leskova E S; Shulga Y M

来源：Journal of Nanoscience and Nanotechnology, 2011, 11(3): 1887-1896.

DOI：10.1166/jnn.2011.3120

• Fullerite Oxidation
• Orientational Phase Transition
• Density Functional Theory
• sp(3)-Hybridization
• Magnetic Impurities
• Fullerene Defects

Oxidized fullerite was obtained by heating a fullerite sample intercalated with oxygen, (O-2)(0.44)C-60, up to 300 degrees C. Orientational phase transitions in the oxidized fullerite are studied using differential scanning calorimetry (DSC) and have been found to possess a specific enthalpy whose value is lower by 25% than in the initial (O-2)(0.44)C-60 sample. In order to find possible reasons for hindrance to the buckyball rotations, we performed optimizations of defect buckyball fullerenes C60-n with different distributions of vacancies along with the dimers C60-n-C60-n and C-60-C60-n for n = 1-4 using density functional theory with generalized gradient approximation. We found that the dimerization energy ranges from 1.07 eV (C-58-C-58) to 6.56 eV (C-56-C-56) and from 1.81 eV (C-60-C-58) to 4.29 eV (C-60-C-56), respectively. The formation of such dimers, which could in addition interact with defect buckyball cages and form larger aggregates, is to be related to the lowering of the orientational transition enthalpy.

• 出版日期2011-3