Investigation on the interaction on and the rotation of C60 in alkali-doped complexes AXA?3-XC60 (X = 1, 2, 3; A, A? = alkali)

Abstract

The interaction on and the rotation of C60 in akali-doped C60 solids, AXA′3-XC60 (X = 1, 2, 3; A, A′ = alkali), have been calculated with Buckingham potential model. The results show that the total interaction on C60 changes dramatically when the pure C60 solid is alkali-doped into K3C60. The interaction on C60 in K3C60 is about 20 times greater than that in pure C60. And the main component in the former, occupying > 90% is electrostatic, while in the latter, the main components, occupying > 90%, are dispersive and repulsive. The results also show that in contrast to the whole-region free rapid rotation of C60 molecule in its pure solid, the rotation of C60 in K3C60 is mostly forbidden due to a 10 times increase (reaching about 300 kJ/mol) in potential barrier, except for the region from 0° to 50° where a broad, smooth, and shallow potential well exists. Calculations for alkali-doped complexes other than K3C60, i.e., AXA′3-XC60 (X = 1, 2, 3; A, A′ = K, Rb, Cs), come to the same conclusion. Finally, an interesting and meaningful result is that the superconducting transition temperatures of AXA′3-XC60 (X = 1, 2, 3; A, A′ = K, Rb, Cs) change inversely with the total interactions on C60. © 1995 John Wiley & Sons, Inc.