The structures and UV spectra of both 5/6 and 6/6 isomers for the amin
o acid derivatives of C-60 have been investigated by the series of IND
O 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 exper
imental results. Meanwhile the theoretical assignment for the electron
ic transition has been performed and the red - shift of the UV spectra
has been rationalized.