Regensburg 2016 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 88: Frontiers of Electronic Structure Theory: Focus on Topology and Transport V
O 88.13: Vortrag
Donnerstag, 10. März 2016, 18:00–18:15, H24
Interaction of Tritium and Chlorine 36 with defects in Graphite: Insights from Theory — •Christoph Lechner1, Philippe Baranek1, and Holger Vach2 — 1EDF Lab Les Renardières, Avenue des Renardieres, F-77818 Moret-sur-Loing Cedex, France — 2CNRS-LPICM, Ecole Polytechnique, F-91128 Palaiseau Cedex, France
In order to optimize the waste management of nuclear graphite used in power plants, it is important to understand the properties of the activated impurities it contains, such as tritium and chlorine 36. Therefore, a computational study of the interaction of tritium and chlorine 36 with defects in graphite has been achieved at the density functional theory (DFT) level by using the functionals PBE and PBE0 with Grimme's D3 dispersion correction. The physisorption and chemisorption of atomic and molecular hydrogen or chlorine on graphite surfaces, (001), (100), and (110) with or without mono- and divacancies, have been investigated. The stabilities of the formed complexes are interpreted in terms of the formation energy. To obtain insight into the nature of the bonding a population analysis of the systems has been performed. While the bonding of hydrogen is mostly covalent for chemisorption and van der Waals for physisorption, the behavior of chlorine is much more complex. Depending on the defect site, both, dominantly covalent and dominantly charge transfer bonding, is observed. Raman spectra for selected structures have been investigated, in order to evaluate, if the experimentally observed defect bands can be reproduced.