EXCITED-STATE PHOTOEMISSION WITH COMBINED LASER SYNCHROTRON PULSE EXCITATION FROM C-60 CHEMISORBED ON NI(110)/

Photoemission from C-60 chemisorbed on Ni(110) has been studied by one -photon photoelectron spectroscopy (1ppe) and two-photon photoelectron spectroscopy (2ppe) with synchrotron radiation (SR) and with synchron ized SR and laser radiation. The 1ppe photoelectron spectra are studie d as a function of C-60 coverage. Significant peak broadening relative to the thick film features is observed for the three leading valence bands. The large peak width of the valence levels obtained for the mon olayer system is consistent with changes of the physical structure of C-60 due to the strong chemical interactions with the nickel substrate . The 2ppe experiment demonstrates transient excitation of the (t(2u), h(g)) level of C-60. (C) 1998 American Institute of Physics. [S0021-89 79(98)04703-3].