DFT-D3 study of two-dimensional polymerization of C60 crystal under high pressure

Abstract

Abstract The high-pressure behavior of a monomer and 2D polymerized C60 crystals were investigated using DFT-D3 calculations. Although covalent bonds were not observed in monomer P a 3 ¯ upon simple compression, C60 moieties in two-dimensional polymer phases (Immm and R 3 ¯ m phases) exhibited intermolecular electron density, which indicates the formation of covalent bonds between C60 moieties. The C60 crystals were highly compressed under high pressure; however, small compression was observed at the C60 moieties. Both internal energies and PV terms contributed similarly to enthalpy. The deformation of crystals prevented polymerization. These results suggested a different behavior from that of typical inorganic materials.