2-PHOTON PHOTOEMISSION FROM BENZENE ADSORBED ON CU(111)

We have observed occupied and excited states induced by benzene adsorp tion on Cu(lll) by means of two-photon photoemission. The benzene-deri ved occupied state is observed as a clear peak at 0.23 eV below E-F, i n between the peak of the copper surface state and the stepwise Fermi edge. The occupied state is attributed to the bonding orbital between benzene and copper substrate. The excited state is at 1.0 eV above E-F The occupied state and the excited state arise from bonding and antib onding orbitals formed by hybridization of the copper surface state or bital and benzene e(2u) pi orbital. (C) 1998 Elsevier Science B.V.