C_{60} with O defects: Localized states in the gap and oxygen clustering

Abstract

We propose a Su-Schrieffer-Heeger type electron-phonon model for C_{60} with O defects and solve by the adiabatic approximation. Two new properties are obtained. (1) The dimerization becomes weaker around the oxygen. Two localized states appear deep in the gap. Optical transition between them is allowed. This accords with the recent optical absorption data. (2) Oxygens are predicted to cluster on the surface of $\soc$. PACS numbers: 3640, 7155, 6165, 3120P