2011/04/30 by Jörg Meyer, Karsten Reuter
Chemistry · Engineering · Physics and Astronomy · #Adiabatic process #Adsorption #Advanced Chemical Physics Studies #Atomic physics #Chemisorption #Chemistry #Condensed matter physics #Dissipation #Dissociation (chemistry) #Electron #Excitation #Molecular Junctions and Nanostructures #Physical chemistry #Physics #Quantum mechanics #Spectroscopy and Quantum Chemical Studies #cond-mat.mes-hall #cond-mat.mtrl-sci #physics.chem-ph #physics.comp-ph
paper · pdf · doi:10.1088/1367-2630/13/8/085010
published as New J. Phys. 13, 085010 (2011) · 20 pages including 7 figures; related publications can be found at http://www.fhi-berlin.mpg.de/th/th.html [added two references, changed V_{fsa} to V_{6D}, modified a few formulations in interpretation of spin asymmetry of eh-spectra, added missing equals sign in Eg.(2.10)]
arxiv created 2011/08/11 · openalex publication_date 2011/08/16 · arxiv updated 2015/03/18 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
During the exothermic adsorption of molecules at solid surfaces, dissipation of the released energy occurs via the excitation of electronic and phononic degrees of freedom. For metallic substrates, the role of the non-adiabatic electronic excitation channel has been controversially discussed, as the absence of a band gap could favour an easy coupling to a manifold of electron–hole pairs of arbitrarily low energies. We analyse this situation for the highly exothermic showcase system of molecular oxygen dissociating at Pd(100), using time-dependent perturbation theory applied to first-principles electronic-structure calculations. For a range of different trajectories of impinging O 2 molecules, we compute largely varying electron–hole pair spectra, which underlines the necessity to consider the high-dimensionality of the surface dynamical process when assessing the total energy loss into this dissipation channel. Despite the high Pd density of states at the Fermi level, the concomitant non-adiabatic energy losses nevertheless never exceed about 5% of the available chemisorption energy. While this supports an electronically adiabatic description of the predominant heat dissipation into the phononic system, we critically discuss the non-adiabatic excitations in the context of the O 2 spin transition during the dissociation process.