title: Mapping the excited states of single hexa-peri-benzocoronene oligomers.
abstract: Electronic states of a molecule are usually analyzed via their decomposition in linear superposition of multielectronic Slater determinants built up from monoelectronics molecular orbitals. It is generally believed that a scanning tunneling microscope (STM) is able to map those molecular orbitals. Using a low-temperature ultrahigh vacuum (LT-UHV) STM, the dI/dV conductance maps of large single hexabenzocoronene (HBC) monomer, dimer, trimer, and tetramer molecules were recorded. We demonstrate that the attribution of a tunnel electronic resonance to a peculiar π molecular orbital of the molecule (or σ intermonomer chemical bond) in the STM junction is inappropriate. With an STM weak-measurement-like procedure, a dI/dV resonance results from the conductance contribution of many molecular states whose superposition makes it difficult to reconstruct an apparent molecular orbital electron probability density map.
authors.affiliation: IMRE, A*STAR (Agency for Science, Technology and Research), 3 Research Link, 117602, Singapore. wh-soe@imre.a-star.edu.sg
authors.forename: We-Hyo
authors.initials: WH
authors.lastname: Soe
authors.forename: Hon Seng
authors.initials: HS
authors.lastname: Wong
authors.forename: Carlos
authors.initials: C
authors.lastname: Manzano
authors.forename: Maricarmen
authors.initials: M
authors.lastname: Grisolia
authors.forename: Mohamed
authors.initials: M
authors.lastname: Hliwa
authors.forename: Xinliang
authors.initials: X
authors.lastname: Feng
authors.forename: Klaus
authors.initials: K
authors.lastname: Müllen
authors.forename: Christian
authors.initials: C
authors.lastname: Joachim