Abstract: The INDO series methods are used to study the two structures of C₆₀O: one is C_2v, geometry with a bridging oxygen across the bond between two fused six-membered rings in C₆₀; the othor is C, geometry with a bridging oxygen across the bond betweena five- and a six-membered rings. From the calculated results (including total energy, HOMO-LUMO gap and the spectral character), the most stable isomer of C₆₀O should be the C_2vgeometry. Our calculations also showed that this C_2visomer has an epoxide-like structure (bridging C₁₅-C₃₀=0. 1518 nm, bond-order=0. 8744). The calculated results of electronic spectrum of the C_2vgeometry are in good accordance with experimental results.

Key words: C₆₀O(C_2v), C₆₀O(C₃), Electronic spectra