title: Charge Redistribution and Transport in Molecular Contacts.
abstract: The forces between two single molecules brought into contact, and their connection with charge transport through the molecular junction, are studied here using non contact AFM, STM, and density functional theory simulations. A carbon monoxide molecule approaching an acetylene molecule (C_{2}H_{2}) initially feels weak attractive electrostatic forces, partly arising from charge reorganization in the presence of molecular . We find that the molecular contact is chemically passive, and protects the electron tunneling barrier from collapsing, even in the limit of repulsive forces. However, we find subtle conductance and force variations at different contacting sites along the C_{2}H_{2} molecule attributed to a weak overlap of their respective frontier orbitals.
authors.affiliation: Institut für Experimentalphysik, Freie Universität Berlin, 14195 Berlin, Germany.|Centro de Fisica de Materiales CSIC/UPV-EHU, 20018 Donostia-San Sebastian, Spain.|Ikerbasque, Basque Foundation for Science, 48011 Bilbao, Spain.
authors.forename: Martina
authors.initials: M
authors.lastname: Corso
authors.affiliation: Institute of Physics of the Academy of Sciences of the Czech Republic, 162 00 Prague, Czech Republic.
authors.forename: Martin
authors.initials: M
authors.lastname: Ondráček
authors.affiliation: Institut für Experimentalphysik, Freie Universität Berlin, 14195 Berlin, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Lotze
authors.affiliation: Institute of Physics of the Academy of Sciences of the Czech Republic, 162 00 Prague, Czech Republic.
authors.forename: Prokop
authors.initials: P
authors.lastname: Hapala
authors.affiliation: Institut für Experimentalphysik, Freie Universität Berlin, 14195 Berlin, Germany.
authors.forename: Katharina J
authors.initials: KJ
authors.lastname: Franke
authors.affiliation: Institute of Physics of the Academy of Sciences of the Czech Republic, 162 00 Prague, Czech Republic.
authors.forename: Pavel
authors.initials: P
authors.lastname: Jelínek
authors.affiliation: Institut für Experimentalphysik, Freie Universität Berlin, 14195 Berlin, Germany.|Ikerbasque, Basque Foundation for Science, 48011 Bilbao, Spain.|CIC nanoGUNE, 20018 Donostia-San Sebastian, Spain.
authors.forename: J Ignacio
authors.initials: JI
authors.lastname: Pascual