Berlin 2012 – scientific programme
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O: Fachverband Oberflächenphysik
O 12: Surface dynamics
O 12.2: Talk
Monday, March 26, 2012, 16:15–16:30, H 2013
Signatures of non-adiabaticity in the scattering of O2 at Ag(111)? — •Itziar Goikoetxea1,2, Jörg Meyer1, J. Inaki Juaristi2, Maite Alducin2, and Karsten Reuter1 — 1Technische Universität München, Germany — 2Centro de Física de Materiales, San Sebastián, Spain
We study the scattering of O2 at Ag(111) using molecular dynamics techniques based on a six-dimensional first-principles adiabatic potential energy surface (PES). In preceding work [1] we had shown that the measured extremely low initial sticking coefficient at this surface can be rationalized by late and large energy barriers of 1.2 eV and an extremely narrow entrance channel leading to dissociation. Unfortunately, these adiabatic PES characteristics render the sticking a rather insensitive quantity with respect to an at times conjectured spin or charge non-adiabaticity in the O2-Ag(111) interaction. We therefore now turn to the regime where the latter is brief and focus on the O2 scattering properties. Intriguingly, the adiabatic simulations reproduce both in-plane and out-of-plane scattering data [2] even to the level of distinct features. These features have been interpreted as indications for two distinct scattering regions: a smooth surface region above the chemisorption well at large distances from the surface, and a more corrugated surface region at closer distances [2]. We qualify these interpretations and the underlying low-dimensional model conceptions based on our high-dimensional first-principles simulations.
[1] I. Goikoetxea et al., accepted at New J. Phys.
[2] A. Raukema et et al. J. Chem. Phys. 103, 6217 (1995).