Adsorption and bonding of molecular icosahedra on Cu(100)

Closo-l,2-dicarbadodecaborane (C₂B₁₀H₁₂, otherwise known as orthocarborane) adsorption and bonding on Cu(100) were investigated over the substrate temperature range 150 to 400 K using atomic beam scattering (ABS), photoemission and Auger electron spectroscopy. At 150-180 K, orthocarborane adsorbed molecularly with one or two carbon atoms forming bonds with the copper surface in the monolayer coverage range. The molecular orientation within the film becomes more disoriented as coverage is increased above 1 monolayer. For adsorption at 250 K or higher, there is clear evidence that orthocarborane dissociatively adsorbs on the Cu(100) surface. The photoemission features attributable to the orthocarborane molecular orbitals have been compared with gas phase measurements and theory.