Dresden 2009 – scientific programme
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O: Fachverband Oberflächenphysik
O 17: Oxides and insulators III
O 17.4: Talk
Tuesday, March 24, 2009, 11:15–11:30, SCH A01
Understanding the Accuracy of Density-Functional Theory Exchange-Correlation Functionals for Adsorption at Ionic Substrates: Water on salt and some other examples — •Bo Li1, Angelos Michaelides1,2, and Matthias Scheffler1 — 1Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6 Berlin, Gemany — 2London Centre for Nanotechnology and Department of Chemistry, University College London, London UK
The interaction of water with salt (NaCl) is of widespread importance. Although numerous theoretical studies have been reported (see Ref. [1] and references therein), none has provided a reliable estimate of the strength of the bond between water and NaCl(001). Moreover, the adsorption energies predicted by density-functional theory (DFT) range from 0.2 to 0.7 eV/H2O depending on exchange-correlation (xc) functional. Here, we address this through a set of second order Møller-Plesset perturbation theory and coupled cluster calculations on a series of NaxClx (x= 5 to 25) clusters to arrive at a reliable estimate of the H2O adsorption energy on NaCl(001). This is then used to understand the performance of a range of xc functionals in treating this and related adsorption systems. Further, through symmetry-adapted perturbation theory the relative importance of electrostatics, covalency, and van der Waals forces in water adsorption on ionic substrates in unraveled.
[1] A. Verdaguer, G. M. Sacha, H. Bluhm, and M. Salmeron, Chem. Rev. 106, 1478 (2006).