Electronic and geometric properties of alkali-C60 molecules

First-principle electronic structure calculations are carried out for MxC60q, where M = Li. Na. X and (x. q) = (1. 0). (1. +/-1). (2, 0).(3, -1). (6, 0). (6, -1). (12 0) using the local density functional, The electric dipole moment for MC60 agrees with the experimental results. The calculated Mulliken charge indicates that, the bonding of the alkali atom with C-60 is mostly ionic except for lithium. The alkali atom prefers to make many bonds with the carbon atoms rather than a single build with the neighbor carbon atom. The calculated adsorption energy suggest that the metal-metal bonding of sodiums and potassiums on C-60 arises for more than the six valence electrons in the alkali atoms. The lithium-lithium bond is. oil the other hand. not appeared for x less than or equal to 12. The difference in the most stable geometry between lithiums and the other alkali atoms oil C-60 Comes from the covalent character of the lithium-carbon bond.