ELECTRONIC-STRUCTURE OF MOLECULAR ICOSAHEDRA FILMS

Using angle-resolved photoemission and inverse photoemission, the elec tronic structure of films of the molecular icosahedron orthocarborane (C2B10H12) On Cu(100) has been studied. The measured gap between the h ighest occupied molecular orbitals and the lowest unoccupied molecular orbitals is in good agreement with modified neglect of differential o verlap calculations. An unoccupied exopolyhedral state has been found and is ascribed to molecular orbital hybridization. This hybridization is consistent with the observed dispersion of the orthocarborane mole cular orbitals. This molecular orbital dispersion indicates a surface Brillouin zone edge with an average radius of 0.7 Angstrom(-1), and su ggests that the molecules adopt local close-packed ordering in the ove rlayers, with an intermolecular distance of 5.58 Angstrom.