Charge transfer and doping-dependent hybridization of C₆₀ on noble metals

K-doped C-60 monolayers on polycrystalline Cu, Ag, and Au are studied by means of ultraviolet photoelectron spectroscopy. The polycrystalline character of the substrate allows an accurate subtraction procedure to isolate the photoemission signal of the monolayer. Charge transfers of 1.0-1.8 electrons per molecule are found for the undoped monolayer. On high K doping the hybridization with the substrate is shown to practically disappear, and the overlayer almost totally suppresses the substrate signal. [S0163-1829(98)02120-1]