E. Pehlke

Surface-state localization at adatoms.

Low-temperature scanning tunneling spectroscopy of magnetic and nonmagnetic metal atoms on Ag(111) and on Cu(111) surfaces reveals the existence of a common electronic resonance at an energy below the binding energies of the surface states. Using an extended Newns-Anderson model, we assign this resonance to an adsorbate-induced bound state, split off from the bottom of the surface-state band, and broadened by the interaction with bulk states. A line shape analysis of the bound state indicates that Ag and Cu adatoms on Ag(111) and Cu(111), respectively, decrease the surface-state lifetime, while a cobalt adatom causes no significant change.

Unoccupied states of individual silver clusters and chains on Ag(111)

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 calculations reproduce the observed energies within

Evolution of unoccupied resonance during the synthesis of a silver dimer on Ag(111)

0.6\phantom{\rule{0.3em}{0ex}}\mathrm{eV}

Molecular-dynamics simulations of non-adiabatic processes at surfaces

and enable an assignment of the resonances to hybridized atomic

Non-adiabatic Effects at Surfaces Simulated with TDDFT Molecular Dynamics

5s

Coadsorbate‐Induced Reversal of Solid–Liquid Interface Dynamics

and

Reaction dynamics of H2 on Si. Ab initio supported model calculations

5{p}_{z}

Molecular dynamics of nonadiabatic processes at surfaces : Chemisorption of H/Al(111)

orbitals with silver substrate states.

Surface state electron dynamics of clean and adsorbate-covered metal surfaces studied with the scanning tunnelling microscope

Silver dimers were fabricated on Ag(111) by single-atom manipulation using the tip of a cryogenic scanning tunnelling microscope. An unoccupied electronic resonance was observed to shift toward the Fermi level with decreasing atom–atom distance as monitored by spatially resolved scanning tunnelling spectroscopy. Density functional calculations were used to analyse the experimental observations and revealed that the coupling between the adsorbed atoms is predominantly direct rather than indirect via the Ag(111) substrate. While the substrate influence is small owing to the surface-projected sp band gap, the direct interaction is most likely due to the large extension of the p wave functions at the adsorbate atoms contributing to the resonance.

Adsorption and diffusion of SCH 3 radicals and Au ( SCH 3 ) 2 complexes on the unreconstructed Au(111) surface in the submonolayer coverage regime

Time-dependent density functional theory, together with the adiabatic approximation for the time-dependent exchange-correlation potential, is combined with Ehrenfest dynamics for the nuclear motion to numerically simulate electronically non-adiabatic processes at surfaces. We have applied this method to electron–hole pair excitation at Al(111) surfaces evoked by the chemisorption of hydrogen atoms, a process which has been demonstrated experimentally by Nienhaus, McFarland et al. by measuring the induced chemicurrent, as well as the excitation of Si(001) surface atom vibrations induced by intense fs laser pulses. The simulations allow a detailed analysis of the non-adiabatic contribution to the Ehrenfest force acting on the atoms, the energy dissipation and the electron–hole excitation spectrum after a given simulation period. Due to the huge computational effort, the simulations are currently limited to a few hundred fs.