Distinguishing two isomers of Nd@C82 by scanning tunneling microscopy and density functional theory

Two different structural isomers of Nd@C82 have been isolated using two-stage high-performance liquid chromatography. Their molecular orbital structures have been studied by a combination of scanning tunneling microscopy (STM) and density functional theory (DFT). Matching filled and empty-states STM images to DFT calculations allowed us to distinguish directly between the two isomers on the surface.