Orientational Disorder and Electronic States in ${\mathrm{C}}_{60}$ and ${\mathit{A}}_3$${\mathrm{C}}_{60}$, where A is an Alkali Metal

Orientational disorder appears to persist in solid ${\mathrm{C}}_{60}$ even at low temperature, and similar static disorders is likely to exist in ${\mathit{A}}_3$${\mathrm{C}}_{60}$. The effects of such disorder on their electronic structures are studied by three-band tight-binding models for the ${\mathrm{C}}_{60}$ and ${\mathit{A}}_3$${\mathrm{C}}_{60}$ conduction bands. The densities of states for the disordered systems are quite different from those in the ordered systems. Participation-ratio analyses suggest that most of the states are delocalized, but there should nonetheless be a host of experimental consequences associated with short mean free paths.