Abstract
Using the Car-Parrinello method we have investigated theoretically the properties of and crystals. Our results are in very good agreement with available experimental data. We find an interesting pattern of relaxations both in the fullerene cage and in the position of the K ions with respect to an ideal configuration. The relaxation energy gain is ≊1 eV and is due in comparable amounts to the and the K’s. These energy gains are achieved by relatively small ionic dispalcements. Analysis of the electronic charge density reveals non-rigid-band effects. Similarities and differences with graphite intercalation compounds are discussed.
- Received 19 August 1991
DOI:https://doi.org/10.1103/PhysRevLett.68.823
©1992 American Physical Society