Self-assemblies of n-hexadecane and n-hexatricontane on the Au(1 1 1) surfa
ces in their neat liquid or solution have been studied by using scanning tu
nneling microscopy (STM). Ordered monolayers are observed on the reconstruc
ted Au(1 1 1) surfaces, while no overlayer could be observed on the unrecon
structed surface at room temperature. The reconstructed surface is found to
be perfect for the n-alkanes to self-assemble on it, because the alkane mo
nolayer geometrically matches well to the reconstructed surface. The recons
truction stabilizes the self-assembled monolayer on the Au(1 1 1) surface,
which facilitates the observation of STM.