Electronic and geometric structures ofC70

We have calculated the electronic structure of the ${\mathrm{C}}_{70}$ cluster of the ${\mathit{D}}_{5\mathit{h}}$ geometry by the local-density approximation. The electronic levels obtained show excellent agreement with photoemission experiments, which provides a further strong support for this geometry. The bunching of levels is observed at several energies, including the region around the highest-occupied state and the lowest-unoccupied state, showing the possibility of superconductivity in doped solid ${\mathrm{C}}_{70}$. The total-energy calculation suggests that the bond-length alternation found in ${\mathrm{C}}_{60}$ is also present in ${\mathrm{C}}_{70}$. The calculated binding energy per atom of the ${\mathrm{C}}_{70}$ cluster is found to be slightly larger than that of the ${\mathrm{C}}_{60}$ cluster. This implies the importance of dynamical effects on the relative abundance of fullerenes.