Structural and electronic properties of oxygen-doped heterofullerene: is the O–C single bond shorter than the C–C single bond?

Single O-doped heterofullerene C59O is investigated via semiempirical PM3 calculations. In contrast to previous less accurate INDO/2 calculations where the O–C single bond is shorter than the C–C single bond of the fullerene cage, our static geometric optimization obtained a slightly longer O–C single bond, a general result for heterofullerenes. The HOMO lies in the middle of the energy gap of the undoped system, and its probability density is strongly localized on the dopant O site. Also investigated are the geometric and electronic properties of the C58O2 isomer with two doped O atoms occupying the para-vertexes of a hexagon.