Effect of impurity oxygen molecules on the structural and thermodynamic properties of fullerite C60

Abstract

Articles you may be interested inEffect of nitrogen sorption mechanisms on the properties of fullerite C60 over a wide range of temperatures Low Temp. Phys. 40, 685 (2014); 10.1063/1.4894316 The effect of glass transition in fullerite C60 on Ar impurity diffusion Low Temp. Saturation of fullerite C60 with hydrogen: Adsorption crossover studies Low Temp. Phys. 38, 952 (2012); Fiz. Nizk. Temp. 36, 335-342 ͑March 2010͒Intercalation of fullerite C 60 with oxygen molecules is performed by two methods-under ordinary conditions of saturation at room temperature and gas pressure 1 atm as well as at elevated temperature ͑373 K͒ and pressure ͑10 atm͒. The time dependences of the lattice parameter of fullerite during intercalation are determined. This made it possible to evaluate the activation energy and the coefficient of diffusion of oxygen molecules in fullerite C 60 . It is shown that increasing the temperature and pressure of the gas increases the diffusion coefficient almost fivefold: from D Ϸ͑1.6Ϯ 1.9͒ ·10 −14 cm 2 / s at atmospheric pressure and room temperature to D Ϸ͑7.1Ϯ 1.9͒ ·10 −14 cm 2 / s for pressure P = 10 atm and temperature T = 373 K. The oxygen concentration in octahedral voids and the temperatures of phase transitions in solutions are determined on the basis of an analysis of the results obtained together with published data on the effect of atomic and molecular impurities on the properties of C 60 . The effect of oxygen impurity on the properties of an orientational phase transition and the temperature dependence of the lattice parameter is investigated.