Abstract
First-principles electronic-structure calculations for crystalline are reported, based on the geometry determined by x-ray-diffraction measurements. The ground state is found to be insulating, with an indirect gap of 0.48 eV. The character of both occupied and unoccupied states near the valence-band maximum is completely carbonlike. The K atoms are almost fully ionized, and the molecule is stabilized in an unusually high charge state with six additional electrons. Implications of the distribution of excess charge on the molecule for orientational ordering are discussed.
- Received 30 May 1991
DOI:https://doi.org/10.1103/PhysRevLett.67.1610
©1991 American Physical Society