Theoretical study of the structural and electronic properties of two-dimensionally polymerized fullerene clusters with 2, 3, 4, and 7C60molecules

Abstract

The structural and electronic properties of clusters of up to 7 crosslinked ${\mathrm{C}}_{60}$ molecules are calculated at the semiempirical AM1 and PM3 levels within the linear scaling divide and conquer scheme (DCM) of Yang. An uniaxial contraction of $\ensuremath{\sim}1.2%$ along the $\stackrel{\ensuremath{\rightarrow}}{c}$ direction of the monomer ${\mathrm{C}}_{60}$ due to the polymerization is found through our geometry optimization procedure with no symmetry restrictions. The clustering formation of four ${\mathrm{C}}_{60}$ through the suggested [2+2] cycloaddition mechanism is a very favorable event, which is consistent with other theoretical results. HOMO-LUMO gap energies decrease as the cluster size increases, predicting the possible onset of conductor behavior as size increases. Our results are in agreement with the two-dimensional ${\mathrm{C}}_{60}$ polymer model proposed by Oszlanyi and Forro. The usefulness of the DCM to study these materials is shown.