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The density theory calculations: the role of the non-local correlation

The Density Functional Theory is the standard approach for the first principles calculations of solid matter, including surfaces and adsorbates. There is a lot work going on in improving the density functionals beyond the currently most widely used Generalized Gradient Approximations (GGA) [1]. In particular, tractable schemes have been proposed for including the nonlocal correlation into the functional [2, 3]. Recently we have applied the approach which calculates the non-local contribution to the correlation energy by dividing the system into weakly coupled ‘ fragments’ of atoms or clusters [2] to the chemisorption of Xe monolayers on Cu(111) and Pt(111) surfaces [4], and obtained excellent agreement with various experimental data. In this work we extend these investigations, using also the more elaborate approach in which the non-local correlation is incorporated into the density functional in a ‘ seamless’ fashion [3]. This makes it possible to apply the approach to systems which cannot be separated in almost independent parts, at the expense of numerical complexity. We apply the approaches to various systems, including dimers and layers of noble-gas atoms, physisorbed atoms and layers, etc. We also investigate the applicability of the approach of Ref.[3] to strongly bound systems. While a general conclusion about the best approach cannot be reached yet, out results clearly show the importance of the non-local correlation in the systems considered, as evidenced by a large improvement over the standard GGA functional. [1] J.P. Perdew et al., J. Chem. Phys. 123, 062201 (2005). [2] E. Hult et al., Phys. Rev. B 59, 4708 (1999), Phys. Rev. B 64, 195414 (2001). [3] M. Dion et al., Phys. Rev. Letters 92, 246401 (2004). [4] P. Lazic, Ž. Crljen, R. Brako, B. Gumhalter, Phys. Rev. B 72, 245407 (2005).

Density functional theory; non-local correlation

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