Self-assembled monolayers are employed in the fabrication of organic transistors and organic- electronic devices. Polycyclic aromatic hydrocarbons (PAHs), a class of organic precursors made by multiply fused aromatic rings, have been particularly promising for optoelectronics applications. The diffusional properties of organic precursors are central in the self-assembly process. We have previously elucidated information on the dynamics of fluoranthene (a common PAH) on graphite and now seek to make complementary measurements of adsorbate structure. This work forms part of an extended study where measurements of benzene and pyrene have allowed us to postulate a correlation between molecular size and diffusion rate. The presence of a five-carbon ring in fluoranthene allows us to see the effect on the surface structure and dynamics of breaking the match in adsorbate-substrate symmetry.