title: Imaging the wave functions of adsorbed molecules.
abstract: The basis for a quantum-mechanical description of matter is electron wave functions. For atoms and molecules, their spatial distributions and phases are known as orbitals. Although orbitals are very powerful concepts, experimentally only the electron densities and -energy levels are directly observable. Regardless whether orbitals are observed in real space with scanning probe experiments, or in reciprocal space by photoemission, the phase information of the orbital is lost. Here, we show that the experimental momentum maps of angle-resolved photoemission from molecular orbitals can be transformed to real-space orbitals via an iterative procedure which also retrieves the lost phase information. This is demonstrated with images obtained of a number of orbitals of the molecules pentacene (C22H14) and perylene-3,4,9,10-tetracarboxylic dianhydride (C24H8O6), adsorbed on silver, which are in excellent agreement with ab initio calculations. The procedure requires no a priori knowledge of the orbitals and is shown to be simple and robust.
authors.affiliation: Institute of Physics, Karl-Franzens University Graz, 8010 Graz, Austria.
authors.forename: Daniel
authors.initials: D
authors.lastname: Lüftner
authors.forename: Thomas
authors.initials: T
authors.lastname: Ules
authors.forename: Eva Maria
authors.initials: EM
authors.lastname: Reinisch
authors.forename: Georg
authors.initials: G
authors.lastname: Koller
authors.forename: Serguei
authors.initials: S
authors.lastname: Soubatch
authors.forename: F Stefan
authors.initials: FS
authors.lastname: Tautz
authors.forename: Michael G
authors.initials: MG
authors.lastname: Ramsey
authors.forename: Peter
authors.initials: P
authors.lastname: Puschnig
mesh_terms: D004583:Electrons; D008962:Models, Theoretical; D009279:Naphthacenes / Q000737:chemistry; D010569:Perylene / Q000737:chemistry; D056951:Photoelectron Spectroscopy; D011789:Quantum Theory; D012834:Silver / Q000737:chemistry; D013499:Surface Properties
chemical_list: D009279:Naphthacenes; D012834:Silver; D010569:Perylene; C523499:pentacene
keywords: density functional theory; organic molecules; photoemission spectroscopy; surface science