Theoretical Study on the Structures and Electron Spectra of C_(60)M_(12) (M = Li, Na, Be)

摘要

Intermediate neglect of differential overlap (INDO) method was used to study the structures and the electronic spectra of C_(60)M_(12) (M = Li, Na, Be). The calculations indicate that in the minimal energy configuration of C_(60)M_12) (M = Li, Na) the C_(60) cage still retains I_h symmetry and the 12 Li or Na atoms are symmetrically located above the pentagons of the C_(60) cage, whereas the difference between the double and single bonds has been significantly reduced. In contrast, because six electrons are filled in the fivefold-degenerated h_g orbital of C_(60), the C_g structure of C_(60)Be_(12) has illustrated the occurrence of Jahn-Teller distortion. Based on the optimized geometries, the electronic absorption spectra were calculated and the nature of red shift was discussed.