The nonlocal correlation energy in the van der Waals density functional (vdW-DF) method can be interpreted in terms of a coupling of zero-point energies of characteristic modes of semilocal exchange-correlation (xc) holes. These xc holes reflect the internal functional in the framework of the vdW-DF method. We explore the internal xc hole components, showing that they share properties with thos...

Two hybrid van der Waals density functionals (vdW-DFs) are developed using 25% Fock exchange with (i) the consistent-exchange vdW-DF-cx functional [K. Berland and P. Hyldgaard, Phys. Rev. B 89, 035412 (2014)] and (ii) with the vdW-DF2 functional [K. Lee et al., Phys. Rev. B 82, 081101 (2010)]. The ability to describe covalent and non-covalent binding properties of molecules is assessed. For pro...

In this paper, we show that first-principle calculations using a van der Waals density functional (vdW-DF) [M. Dion, H. Rydberg, E. Schroder, D. C. Langreth, and B. I. Lundqvist, Phys. Rev. Lett. 92, 246401 (2004)] permit the determination of molecular crystal structure within density functional theory (DFT). We study the crystal structures of hexamine and the platonic hydrocarbons (cubane and ...

The physisorption of the nucleobases adenine (A), cytosine (C), guanine (G), thymine (T), and uracil (U) on graphene is studied using several variants of the density functional theory (DFT): the generalized gradient approximation with the inclusion of van der Waals interaction (vdW) based on the TS approach (Tkatchenko and Scheffer 2009 Phys. Rev. Lett. 102 073005) and our simplified version of...

Using the van der Waals density functional with C09 exchange (vdW-DF-C09), which has been applied to describing a wide range of dispersion-bound systems, we explore the physical properties of prototypical ABO3 bulk ferroelectric oxides. Surprisingly, vdW-DF-C09 provides a superior description of experimental values for lattice constants, polarization and bulk moduli, exhibiting similar accuracy...

It is shown that it is now possible to include van der Waals (vdW) interactions via a nonempirical implementation of density functional (DF) theory to describe the correlation energy in electronic structure calculations on infinite systems of no particular symmetry. The vdW-DF theory [Phys. Rev. Lett. 92, 246401 (2004)] is applied to the adsorption of benzene and naphthalene on an infinite shee...

The adsorption of benzene and C60 on graphene and boron nitride is studied using density functional theory with the van der Waals density functional (vdW-DF). By comparing these systems we can systematically investigate their adsorption nature and differences between the two functional versions vdW-DF1 and vdW-DF2. The bigger size of the C60 molecule makes it bind stronger to the surface than b...

The non-local van der Waals density functional (vdW-DF) of Dion et al (2004 Phys. Rev. Lett. 92 246401) is a very promising scheme for the efficient treatment of dispersion bonded systems. We show here that the accuracy of vdW-DF can be dramatically improved both for dispersion and hydrogen bonded complexes through the judicious selection of its underlying exchange functional. New and published...

Biomolecular systems that involve thousands of atoms are difficult to address with standard density functional theory (DFT) calculations. With the development of sparse-matter methods such as the van der Waals density functional (vdW-DF) method [M. Dion et al., Phys. Rev. Lett. 92, 246401 (2004)], it is now possible to include the dispersive forces in DFT which are necessary to describe the coh...

Sparse matter is characterized by regions with low electron density and its understanding calls for methods to accurately calculate both the van der Waals vdW interactions and other bonding. Here we present a first-principles density-functional theory DFT study of a layered oxide V2O5 bulk structure which shows charge voids in between the layers and we highlight the role of the vdW forces in bu...