Theory of van der Waals bonding: from bulk materials to biomolecules
Doktorsavhandling, 2012

Sparse matter is abundant in Nature. It encompasses systems characterized by an intrinsic low density of electrons in sizeable regions, where the van der Waals forces contribute considerably to cohesion. Given the length scale of the problem, a prediction of these materials requires appropriate tools within a quantum-mechanical framework. Density Functional Theory (DFT) has proven to provide a powerful approach to a non-empirical characterization of condensed-matter properties. However, in spite of the successes achieved by its local (LDA) and semilocal (GGA) approximations, the description of the van der Waals bonding was until recently far from being satisfactory. This is related to the incapability of the local and semilocal exchange-correlation energy functionals to capture the effect of charge fluctuations that arise spontaneously in matter and that are coupled by the electrodynamic field. The problem has been successfully addressed by a density functional (vdW-DF) that accounts for the dispersive interactions by introducing a nonlocality in the correlation term. The work presented in this Thesis contributes to shed light on the van der Waals bonding in soft matter by means of the vdW-DF functional. In particular, it investigates three structurally and electronically different systems (namely belonging to the class of bulks, surfaces and biomolecules) in order to test structural characteristics, cohesive energies, physisorption-related properties and corrugation. A major issue when treating large sparse matter systems coincides with the limit introduced by the selfconsistent calculation of the kinetic term which increases the computing time and memory needed. An attempt to speed-up the computations is presented by taking advantage of the Harris scheme, a nonselfconsistent DFT formulation valid for weakly interacting systems. The account of dispersion forces has a direct impact on the structure resulting in an undoubtedly better description of the atom configuration and the morphology of sparse matter. In addition, it is documented that their fingerprint can also be detected in subtle changes of the band structure and the density of states.

alkanes

extended systems

DNA

band structure

van der Waals Density Functional (vdW-DF)

exchange functionals

Density Functional Theory

non-local correlation

layered oxides

Kollektorn (A423), Kemigården 9
Opponent: Associate Professor Jon Andreas Støvneng

Författare

Elisa Londero

Chalmers, Mikroteknologi och nanovetenskap (MC2), Kvantkomponentfysik

Vanadium pentoxide (V2O5): a van der Waals density functional study

Computer Physics Communications,; Vol. 182(2011)p. 1805-1809

Artikel i vetenskaplig tidskrift

Desorption of n-alkanes from graphene: a van der Waals density functional study

Journal of Physics Condensed Matter,; Vol. 24(2012)p. 424212-

Artikel i vetenskaplig tidskrift

Role of van der Waals bonding in the layered oxide V2O5: First-principles density-functional calculations

Physical Review B - Condensed Matter and Materials Physics,; Vol. 82(2010)p. 054116-

Artikel i vetenskaplig tidskrift

Ämneskategorier

Den kondenserade materiens fysik

ISBN

978-91-7385-786-4

Technical report MC2 - Department of Microtechnology and Nanoscience, Chalmers University of Technology: ISSN 1652-0769

Doktorsavhandlingar vid Chalmers tekniska högskola. Ny serie: 3467

Kollektorn (A423), Kemigården 9

Opponent: Associate Professor Jon Andreas Støvneng

Mer information

Skapat

2017-10-06