ELECTRONIC STATES AND STABILITY OF THE INSULATING RBC60 DIMER PHASE

Photoelectron spectra for the quenched, metastable dimer phase of RbC6 0 show states derived from the lowest unoccupied molecular orbital of C-60 in an similar to 0.5-eV-wide feature centered similar to 1 eV bel ow the Fermi level E(F) The onset of emission at similar to 0.6 eV est ablishes a minimum gap for defect-free material. Identification of a s ignature for the dimer state has implications for the interpretation o f previous photoemission experiments.