Theoretical study on the structure and UV spectra of some amino acid derivatives of C-60

The structures and UV spectra of both 5/6 and 6/6 isomers for the amino acid derivatives of C-60 have been investigated by the series of INDO methods. It is illustrated that the adductive products - [6.6] and [6.5] closed isomers both have C-S symmetries and the energy of [6.6] - closed isomer is lower than that of the [6.5] - closed isomer thus it is more stable. Using the optimized geometry, the UV spectra of both isomers have been calculated and which are in agreement with the experimental results. Meanwhile the theoretical assignment for the electronic transition has been performed and the red - shift of the UV spectra has been rationalized.