Interaction and superconducting transition in alkali-doped C-60

The intermolecular interactions in alkali-doped C-60 solids, A(3 - x - y)A( x)'A(y)" C-60 (A, A', A " = alkali; x + y less than or equal to 3), have be en calculated, and their correlations with the structures and the supercond ucting transition temperatures T-c have also been investigated. It is found that the variations of the lattice constants a(0) of A(3 - x - y)A(x)'A(y) " C-60 solids and the superconducting transition temperatures T-c can be sa tisfactorily explained from the viewpoint of interaction. It is shown that the relationship of T-c with interaction is much closer than that of T-c wi th lattice constant a(0). Therefore, we can say it is the physical factors such as interaction, other than the geometrical structure factors such as a o, that should be reasonably taken as the primitive cause of the sudden cha nge of superconductivity from pristine C60 to its alkali-doped compounds an d of the variation of T-c among superconductors of A(3 - x - y)A(x)'A(y)" C -60.