Scanning tunneling microscopy images of a novel dimeric liquid crystal on graphite

Scanning tunneling microscopy (STM) images of a side-by-side dimeric liquid crystal adsorbed on graphite suggest an unusual structure for the monolayer. Instead of the contact with the graphite being maximized, two of the alkyl tails appear to be nearly normal to the surface. Calculations suggest that this may be due to the substitution of one of the aromatic rings in the core, which causes an alkoxy tail to prefer an orientation perpendicular to the aromatic core rather than the usual coplanar orientation. STM images taken at various bias voltages correlate strongly to the aromatic "cores" of the molecules, but do not appear to correlate to the highest occupied moleculear orbital or lowest unoccupied molecular orbital.