The bonding and electronic configuration of double-decker single molecule magnets (SMM) LnPc2 (Ln = Tb(III) and Dy(III); Pc = phthalocyanine) and non-SMM YPc2 were measured using the cryogenic, UHV scanning tunneling microscope (STM) and scanning tunneling spectroscopy (STS). Two types of molecules were observed as isolated molecules on the Au(111) surface at 4.7 K; one has a shape of eight-lobe with a height of ∼400 pm and the other is four-lobe with a height of ∼140 pm. The former was assigned as a double decker molecule, while the latter was assigned as dissociated species of the molecule; i. e., MPc and Pc. The dI/dV mapping successfully distinguished MPc and Pc by detecting HOMO-1 and LUMO state, which are originated from the ligand Pc but enhanced only in the molecule of MPc.
