Benzene on Au[111] at 4 K: monolayer growth and tip-induced molecular cascades.
Low-temperature scanning tunneling microscopy has been used to characterize the various structures of submonolayer and near-monolayer coverages of benzene (C6H6) on Au[111] at 4 K. At low coverage, benzene is found to adsorb preferentially at the top of the Au monatomic steps and is weakly adsorbed on the terraces. At near-monolayer coverage, benzene was found to form several long-range commensurate overlayer structures that depend on the regions of the reconstructed Au[111] surface, namely a (radical 52 x radical 52)R13.9 degrees structure over the hcp regions and a (radical 133 x radical 133)R17.5 degrees "pinwheel" structure over the fcc regions. Time-lapse imaging revealed concerted cascade motion of the benzene molecules in the (radical 133 x radical 133)R17.5 degrees pinwheel overlayer. We demonstrate that the observed cascade motion is a result of concerted molecular motion and not independent random motion.
Department of Chemistry, The Pennsylvania State University, 104 Davey Laboratory, University Park, Pennsylvania 16802-6300, USA.
Patrick
P
Han
Brent A
BA
Mantooth
E Charles H
EC
Sykes
Zachary J
ZJ
Donhauser
Paul S
PS
Weiss