Van der Waals contributions
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Ubiquitous Van der Waals interactions between atoms and molecules are important for many molecular and solid structures. These systems are often studied from first principles using the Density Functional Theory (DFT). However, the commonly used DFT functionals fail to capture the essence of Van der Waals effects. Most attempts to correct for this problem have a basic semiempirical character, although computationally more expensive first principles schemes have been recently developed. Of course, the key issue is finding a way to include Van der Waals interactions in DFT without dramatically increasing the computational cost.
The present DFT/vdW-WF approach, based on the use of the Maximally-Localized Wannier functions, tries to combine the simplicity of the semiempirical formalism with the accuracy of the first principles approaches, and appears to be promising, being simple, efficient, accurate, and transferable (for instance, charge polarization effects are naturally included), also considering that the method is free from system-dependent fitted parameters. It has been successfully applied to small molecules, water clusters, bulk systems (Ar,graphite), carbon nanotubes, atoms and fragments (He, Ne, Ar, Kr, Xe, H2, H2O, water layers) weakly bonded (physisorbed) to metal (Al(100), Al(111), Cu(111), Pb(111)), semimetal (graphite/graphene) and other (Cl- and H-terminated Si(111)) surfaces.
The new DFT/vdW-WF2 version is based on the simpler London expression and takes into account the intrafragment overlap of the localized Wannier functions, leading to a considerable improvement in the evaluation of the C6 van der Waals coefficients, as shown by the application to a set of selected dimers. Preliminary results on Ar on graphite and Ne on the Cu(111) metal surface suggest that also the C3 coefficients, characterizing molecule-surfaces van der Waals interactions are better estimated with the new scheme.
| Pier Luigi Silvestrelli
Dipartimento di Fisica
| Alberto Ambrosetti|
Fritz Haber Institute,
References (Theory & Applications)
- Van der Waals Interactions in DFT Made Easy by Wannier Functions, P.L. Silvestrelli, Phys. Rev. Lett. 100, 053002 (2008).
- van der Waals Interactions in DFT using Wannier Functions, P.L. Silvestrelli, J. Phys. Chem. A 113, 5224 (2009).
- van der Waals interactions in density functional theory using Wannier functions: Improved C6 and C3 coefficients by a different approach, A. Ambrosetti, P.L. Silvestrelli, Phys. Rev. B 85, 073101 (2012).
- Van der Waals interactions at surfaces by density functional theory using Wannier functions, P.L. Silvestrelli, K. Benyahia, S. Grubisic, F. Ancilotto, F. Toigo, J. Chem. Phys. 130, 074702 (2009).
- Improvement in hydrogen bond description using van der Waals-corrected DFT: The case of small water clusters, P.L. Silvestrelli, Chem. Phys. Lett. 475, 285 (2009).
- van der Waals Effects in Interfacial Water on the Cl- and H-Terminated Si(111) Surfaces, P.L. Silvestrelli, F. Toigo, F. Ancilotto, J. Phys. Chem. C 113, 17124 (2009).
- Adsorption of Rare-Gas Atoms and Water on Graphite and Graphene by van der Waals-Corrected Density Functional Theory, A. Ambrosetti and P. L. Silvestrelli, J. Phys. Chem. C 115, 3695 (2011).
- Adsorption of rare-gas atoms on Cu(111) and Pb(111) surfaces by van der Waals corrected density functional theory, P.L. Silvestrelli, A. Ambrosetti, S. Grubisic, and F. Ancilotto, Phys. Rev. B 85, 165405 (2012).
- Physisorption, Diffusion, and Chemisorption Pathways of H2 Molecule on Graphene and on (2,2) Carbon Nanotube by First Principles Calculations, Francesca Costanzo, Pier Luigi Silvestrelli, and Francesco Ancilotto, J. Chem. Theory Comp. 8, 1288 (2012).