Polymerized Fullerite Structures

Energetics of carbon peapods: Elliptical deformation of nanotubes and aggregation of encapsulatedC60

“…[7][8][9] The results indicate that the polymerization of C 60 takes place inside the nanotubes. It is well known that high pressure treatment under elevated temperature [31][32][33] and photoirradiation 34,35 for the solid C 60 results in the formation of polymeric phases of C 60 . Here, we have explored how nanotubes affect the energetics of C 60 polymerization.…”

Low Band Gap and Ionic Bonding with Charge Transfer Threshold in the Polymeric Lithium Fulleride Li4C60

“…In fact, while a charge transfer is usually necessary to stabilize the bridging of two adjacent molecules via a single bond, which uses up one electron per participating cage, 70 [2 + 2]cycloaddition bonding between neighboring C 60 molecules is observed in all polymer phases derived from undoped C 60 (where no charge transfer is present). 9,40,71,72 Since each cage is linked by two [2 + 2]cycloaddition bonds and two single bonds, a doping level of two electrons per cage is sufficient for the formation of the 2D-polymer phase in Li 4 C 60 .…”

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14] Singly or doubly bonded dimers [1][2][3][4] and polymer chains, [5][6][7][8] as well as two-dimensional (2D) [9][10][11] and even three-dimensional [12][13][14] networks of C 60 molecules have been reported. The free energy of different structures is often very similar, resulting in an abundance of phase transitions which can be induced by temperature or pressure variations, light irradiation, or chemical doping as in alkali fullerides.…”

“…Undoped C 60 polymerizes either into a rhombohedral phase, characterized by hexagonal networks of molecules linked via [2 + 2]cycloaddition bonds which are coplanar with the hexagonal planes, or into a tetragonal phase, in which half the [2 + 2]cycloaddition bonds are coplanar with the networks while the others are orthogonal to them. 9,15 In Mg fullerides, the formation of a rhombohedral phase is reported, 16 while the 2D polymer phase of Na 4 C 60 consists of planar rectangular networks where each molecule forms four single bonds within the plane. 10 The rectangular polymer networks in Li-doped C 60 were initially thought to consist of [2 + 2]-cycloaddition bonds.…”

First-principles study on atomic configuration of electron-beam irradiated C60film

“…Since the metallic phase of the C 60 polymer is surrounded by the other phase of the C 60 's in the initial stage of the EB irradiation according to the STM image, 7 its lattice parameters are not expected to be fully relaxed. We assume lattice parameters a = 17.37 bohrs, c = 46.30 bohrs, and α = π/3, which correspond to those for the dumbbell-shaped interlayer connection obtained by x-ray diffraction pattern analysis, 17 and employ these lattice parameters for both models (a) and (b) to compare the contributions of the dumbbell-shaped and peanut-shaped connections to the electronic structures. Note that the stacking structure of the polymer presented in this study is not deformed from that of the rhombohedral bulk phase and corresponds to the experimentally observed STM image, whereas the hexagonal polymers in Refs.…”