Abstract
We have calculated the properties of a rhombohedral phase of solid using a C tight-binding potential. The solid is formed by layers of hexagonally packed , each of them connected to six neighbors by 2 + 2 cycloaddition of double bonds. We predict an equilibrium intermolecular distance of 9.17 Å, in agreement with experimental estimates of 9.2 Å. Rhombohedral solid is higher in energy than free molecules by 2.1 eV/molecule, and the barrier for dissociation to free molecules is estimated to be 1.6 eV/molecule. Our results indicate that the lowest energy conformation of this new phase of solid is a semiconductor, but defects in the intermolecular bonding pattern lead to semimetal properties. Results from similar calculations on tetragonal and orthorhombic phases are also presented.
- Received 16 May 1994
DOI:https://doi.org/10.1103/PhysRevLett.74.274
©1995 American Physical Society