title: Surveying molecular vibrations during the formation of metal-molecule nanocontacts.
abstract: Molecular junctions have been characterized to determine the influence of the metal contact formation in the electron transport process through a single molecule. With inelastic electron tunneling spectroscopy and first-principles calculations, the vibration modes of a carbon monoxide molecule have been surveyed as a function of the distance from a copper electrode with unprecedented accuracy. We observe a continuous but nonlinear blue shift of the frustrated rotation mode in tunneling with decreasing distance followed by an abrupt softening upon contact formation. This indicates that the presence of the metal electrode sensibly alters the structural and conductive properties of the junction even without the formation of a strong chemical bond.
authors.affiliation: Max-Planck-Institute fuer Festkoerperforschung, Heisenbergstrasse 1, D-70569 Stuttgart, Germany. lucia_vitali@ehu.es
authors.forename: Lucia
authors.initials: L
authors.lastname: Vitali
authors.forename: Robin
authors.initials: R
authors.lastname: Ohmann
authors.forename: Klaus
authors.initials: K
authors.lastname: Kern
authors.forename: Aran
authors.initials: A
authors.lastname: Garcia-Lekue
authors.forename: Thomas
authors.initials: T
authors.lastname: Frederiksen
authors.forename: Daniel
authors.initials: D
authors.lastname: Sanchez-Portal
authors.forename: Andres
authors.initials: A
authors.lastname: Arnau
mesh_terms: D000327:Adsorption; D002248:Carbon Monoxide / Q000737:chemistry; D004553:Electric Conductivity; D004566:Electrodes; D053768:Metal Nanoparticles / Q000737:chemistry*; D008670:Metals / Q000737:chemistry*; D016252:Microscopy, Scanning Tunneling / Q000379:methods*; D010100:Oxygen / Q000737:chemistry; D013053:Spectrophotometry / Q000379:methods; D013499:Surface Properties; D014732:Vibration
chemical_list: D008670:Metals; D002248:Carbon Monoxide; D010100:Oxygen