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...

Van der Waals (vdW) forces are the dominant interactions between neutral particles on nanometer-tomicrometer length scales. This makes their effects ubiquitous in physics, chemistry, and biology: they are, for instance, responsible for the action of detergents, the selfassembly of viruses, and even the ability of geckos to climb flat surfaces. Their existence was first proposed by Johannes Dide...

Volume dependence of the total energy and vibrational properties of crystalline l,3,5-trinitro-l,3,5-triazine (RDX) are calculated using the density functional theory (DFT). For this molecular crystal, properties calculated with a generalized gradient approximation to the exchange-correlation energy differ drastically from experimental values. This discrepancy arises from the inadequacy in trea...

in this paper, a monotone positive solution is studied for buckling of a distributed model of multi walled carbon nanotube (mwcnt) cantilevers in the vicinity of thin and thick graphite sheets subject to intermolecular forces. in the modeling of intermolecular forces, van der waals forces are taken into account. a hybrid nano-scale continuum model based on lennard–jones potential is applied to ...

Van der Waals (vdW) forces act ubiquitously in condensed matter. Despite being weak on an atomic level, they substantially influence molecular and biological systems due to their long range and system-size scaling. The difficulty to isolate and measure vdW forces on a single-molecule level causes our present understanding to be strongly theory based. Here we show measurements of the attractive ...

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 ...

in this paper, the radial breathing mode (rbm) frequencies of multi-walled carbon nanotubes (mwcnts) are  obtained based on the multiple-elastic thin shell model. for this purpose, mwcnt is considered as a multiple concentric elastic thin cylindrical shells, which are coupled through van der waals (vdw) forces between two adjacent tubes. lennard-jones potential is used to calculate the vdw forc...

among the intermolecular interactions, the casimir and van der waals forces are the most important forces that highly affect the behavior of nanostructures. this paper studies the effect of such forces on the adhesion of cantilever freestanding nanostructures. the nanostructures are made of a freestanding nano-beam which is suspended between two upper and lower conductive surfaces. the linear s...

Title: Non-Covalent van der Waals Interactions at the Nanoscale: A Solved Problem? When: Thursday, 14 April (2016), 15:00h Place: Departamento de Física Teórica de la Materia Condensada, Facultad Ciencias, Module 5, Seminar Room (5th Floor). Speaker: Prof. Alexandre Tkatchenko, Physics and Materials Science Research Unit, University of Luxembourg, L-1511 Luxembourg. Non-covalent van der Waals (...

The treatment of van der Waals interactions in density functional theory is an important field of ongoing research. Among different approaches developed recently to capture these non-local interactions, the van der Waals density functional (vdW-DF) developed in the groups of Langreth and Lundqvist is becoming increasingly popular. It does not rely on empirical parameters, and has been successfu...