Real-space imaging of the molecular organization of naphthalene on Pt(111)

The first application of the scanning tunneling microscope to determine a previously unknown adsorbate orientation is presented for naphthalene adsorbed on Pt(111). Measurements in ultrahigh vacuum explore the details of molecular organization for both ordered and disordered systems and allow tentative assignment of the molecular binding site. Statistical analysis of the molecular packing within close-packed domains is inconsistent with the expected ordered structure for this system. Real-space imaging at submonolayer coverage reveals discrete molecular rotation among allowed orientations and translation between adjacent binding sites at room temperature. © 1991 The American Physical Society.