Regensburg 2010 – scientific programme
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O: Fachverband Oberflächenphysik
O 60: Poster Session III (Methods: Atomic and electronic structure; Methods: electronic structure theory; Methods: Molecular simulations and statistical mechanics; Methods: Sanning probe techniques; Methods: other (experimental); Methods: other (theory) )
O 60.4: Poster
Wednesday, March 24, 2010, 17:45–20:30, Poster B2
Excess electron at the ice surface: an approach via mixed quantum/molecular mechanics simulations — •Volker Mosert and Michel Bockstedte — Theor. Festkörperphysik, FAU Erlangen-Nürnberg, Staudtstr. 7B2, 91058 Erlangen
Electron solvation shows a rich varity of phenomena, like surface vs. interior bound states in water clusters. Ab initio theory greatly helped to understand these phenomena. However, regarding ice-surfaces, it is desirable to go beyond present ab initio models of Ih (0001) and to address, for first insight, the complex morphology of ice films as well as the solvation on the long time scale with a less costly approach.1 Such an alternative is the mixed QM/MM approach.2 It treats the water-water interaction via classical potentials and the electron-water interaction via a pseudopotential quantum-mechanically. Although its relevance has been demonstrated for water clusters,2 applications to the electron solvation at the ice surface are scarce 3 and address the temperature regime where pre-melting occurs. For an evaluation of the method, we address the traping of excess electrons at the Ih surface. For prototypical surface defects, the formation energy as well as the electron binding energy are evaluated using different models of the water-interaction. In comparision to recent DFT-calculations, we obtain a good description with TIP4P potentials.
[1] M. Mehlhorn and K. Morgenstern, Phys. Rev.Lett. 99, 246101 (2007); Bovensiepen et al J. Chem. Phys. C 113, 979 (2009).
[2] L. Turi, W.-S. Sheu, and P. J. Rossky, Science 309, 914.
[3] A. Madarász et al, J. Chem. Phys. 126, 234707 (2007).