C_(60) EXCITED BY LIGHT
光激发下的C60

Light-excited C_(60) is studied by electron-lattice coupling tight-binding model. When one or two electrons are excited from HOMO to LUMO, the lowest energy state is ring bipolaron with the following characteristics: (1) The bond structure is layers with seven different bonds. In comparison with the dimerized state, bond variation is like that of ring polaron: to be the largest in equator, nearly unchanged in poles. (2) Two energy levels get into the gap and form the self-trapping electronic bound states which localize in the equator area. (3) C_(60)'s symmetry reduces from I_h to D_(5d). (4) There exist nonlifiear exciton and 4 NMR lines.