A molecular solid $C_{50}{\mathrm{Cl}}_{10}$ with possible crystalline structures, including the hexagonal-close-packed (hcp) phase, the face-centered-cubic (fcc) phase, and a hexagonal monolayer, is predicted in terms of first-principles calculation within the density functional theory. The stable structures are determined from the total-energy calculations, where the hcp phase is shown to be more stable than the fcc phase and the hexagonal monolayer in energy per molecule. The energy bands and density of states for hcp and fcc $C_{50}{\mathrm{Cl}}_{10}$ are presented. The results show that $C_{50}{\mathrm{Cl}}_{10}$ molecules can form either a hcp or fcc indirect-gap band insulator or an insulating hexagonal monolayer.

• Received 7 December 2005

DOI:https://doi.org/10.1103/PhysRevB.73.165417