VIBRONIC COUPLING IN THE PHOTOEMISSION BANDS OF CONDENSED C-60

We present photoelectron spectra for the highest occupied molecular or bital (HOMO) of C-60 in the gas phase and a two-dimensional (2D) conde nsed layer. For low temperatures the similarity in the spectra is stri king and places a strict upper limit of 0.07 eV on the HOMO electronic bandwidth for the 2D solid, which is a fraction of the theoretically predicted value. This is shown to be consistent with expectations of a polaronic model for the bands and suggests the need for a reassessmen t of the band dispersions in 3D C-60. (C) 1997 Elsevier Science B,V.