STRUCTURAL AND ELECTRONIC-PROPERTIES OF KNC-60

We present local-density pseudopotential calculations of the structural and electronic properties of Potassium fulleride K(n)C60 (n = 1, 2, 3, 6) crystals, with an emphasis on the superconducting K3C60 phase. The calculated enthalpies of reaction for all of the potassium fullerides are within 1.4-1.7 eV per K atom. The pressure-versus-volume equation of state indicates that K3 C60 is less compressible than C60. The band structure Of K3C60 is very similar to that of C60, and we discuss how it changes with pressure. Using calculated valence charge densities, we show that the valence electrons of the K atoms are almost completely transferred to the lowest unoccupied bands of the C60 molecular solid.