Silvered molecules: The controlled metalation of individual phthalocyanine (H2Pc) molecules to form AgPc was observed by low‐temperature scanning tunneling microscopy (STM). Stepwise dehydrogenation was followed by Ag+ implantation; tautomerization and hydrogen atom hopping within the H2Pc inner ring were also induced by electron injection from the STM tip.

Scanning tunneling spectroscopy of the differential conductance is performed at constant current and at constant distance. These modes of operation significantly affect peak positions and line shapes in spectra as well as patterns in spatial maps of the differential conductance. A normalization procedure for constant-current data, which relies on experimental current-distance data, is shown to yield spectral information on the local density of states.

Size-selected silver clusters on Ag(111) were fabricated with the tip of a scanning tunneling microscope. Unoccupied electron resonances give rise to image contrast and spectral features which shift toward the Fermi level with increasing cluster size. Linear assemblies exhibit higher resonance energies than equally sized compact assemblies. Density functional theory calculations reproduce the observed energies and enable an assignment of the resonances to hybridized atomic 5s and 5p orbitals with silver substrate states.Comment: 9 pages, 8 figure

Versilberte Moleküle: Die kontrollierte Metallierung einzelner Phthalocyanin(H2Pc)‐Moleküle unter Bildung von AgPc wurde mit Rastertunnelmikroskopie (STM) bei niedriger Temperatur beobachtet. Auf eine stufenweise Dehydrierung folgt eine Ag+‐Implantation; auch eine Tautomerisierung und ein H‐Atom‐Hopping im inneren H2Pc‐Ring wurden durch Elektroneninjektion ausgehend von der STM‐Spitze induziert.

We study dissociative photoionization of molecular oxygen in a kinematically complete XUV-IR pump-probe experiment. Detecting charged fragments and photoelectrons in coincidence using a reaction microscope, we observe a pump-probe delay-dependent yield of very low energetic O + ions which oscillates with a period of 40 fs. This feature is caused by a time-dependent vibrational wave packet in the potential of the binding O 2 + (a 4 u ) state, which is probed by resonant absorption of a single infrared photon to the weakly repulsive O 2 + (f 4 g ) state. By quantitative comparison of the experimental kinetic-energy-release (KER) and quantum-beat (QB) spectra with the results of a coupled-channel simulation, we are able to discriminate between the calculated adiabatic O + 2 potential-energy curves ( (2012)]. In general, we find a good agreement between experimental and simulated KER and QB spectra. However, we could not reproduce all features of the experimental data with these PECs. In contrast, adjusting a Morse potential to the experimental data, most features of the experimental spectra are well reproduced by our simulation. By comparing this Morse potential to theoretically predicted PECs, we demonstrate the sensitivity of our experimental method to small changes in the shape of the binding potential.