Observation and calculation of internal structure in scanning tunneling microscopy images of related molecules.
The scanning tunneling microscope has been used to distinguish among a series of related molecules on Pt(111) by details of their observed structures. The electronic isomers naphthalene and azulene can be recognized, as can three structural isomers of monomethylazulene, as well as dimethyl- and trimethyl-orientations. A simple methodology based on extended Huckel theory, including the substrate, generates electron and hole density plots which show very good agreement with the data