While the primary focus of our study is to understand the qualitative effects of the molecule-metal interface on the conductance properties of the junctions, we note that the computed conductances from our tunneling model are in good agreement with experimental conductances measured using either scanning tunneling microscopy (STM) break-junction or mechanically controlled break-junction measurements. Examples of experimental results are provided in Table . The observed broad conductance distributions of BDT-gold junctions in STM break-junction measurements likely arise at least in part due to the two binding motifs of the molecule at atop and hollow binding sites of the electrodes. Table Binding energy (E b ), barrier height (φ b ), inter-electrode distance (a), calculated conductance (G), and experimental conductance (G expt ) for BDA-copper and BDT-copper junctions.