High resolution photoelectron spectroscopy of C-60(-)

Vibrationally resolved photoelectron spectra of C-60(-) are reported at thr ee photon energies: 355, 266, and 193 nm. Complicated vibrational structure s were observed for the transition to the C-60 ground state with both the A (g) and H-g modes being active. An extra feature was observed in the energy gap region between the highest occupied and lowest unoccupied orbitals of C-60 in the 266 nm spectra only and it was attributed to an autodetachment process. We also report the most accurate measurement of the electron affin ity of C-60 (2.689+/-0.008 eV). (C) 1999 American Institute of Physics. [S0 021-9606(99)02517-9].