[Theoretical study on the structure and spectra of C72O3]

The optimized geometries and stability of eight different isomers of C72O3, the five-membered ring derivatives of C70 fullerenes, were investigated by using AM1 method. According to the optimized geometries of eight different isomers, AM1 and ZINDO/Cl method were employed to study the vibrational spectra and electronic spectra, respectively. The calculated results indicate that the -C2O3 groups are added preferably to the seats of CI-CII and CIII-CIII bond to form the isomers of A and B. The additive C-C bond is elongated to become primarily a single bond. The stability of isomer B is very similar to that of isomer A that has been prepared experimentally. The calculated vibrational spectra of isomer A, similar to those of isomer B, are consistent well with the results from the experiment. The electronic transitions of isomers of C72O3 were assigned and the red shift of electronic spectra was discussed. The spectra of other isomers were predicted theoretically.