Self-assembly and growth of manganese phthalocyanine （MnPc） molecules on an Au（111） surface is investigated by means of low-temperature scanning tunneling microscopy. At the initial stage, MnPc molecules preferentially occupy the step edges and elbow sites on the Au（111） surface, then they are separately adsorbed on the face-centered cubic and hexagonal closely packed regions due to a long-range repulsive molecule-molecule interaction. After the formation of a closely packed monolayer, molecular islands with second and third layers are observed.
