Scalar couplings between covalently bound nuclear spins are a ubiquitous feature in nuclear magnetic resonance (NMR) experiments, imparting valuable information to NMR spectra regarding molecular structure and conformation. Such couplings arise due to a second-order hyperfine interaction, and, in principle, the same mechanism should lead to scalar couplings between nuclear spins in unbound van ...

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 (...

Using a unified macroscopic QED formalism, we derive an integral equation for the van der Waals energy of a two-level atomic system near a carbon nanotube. The equation is valid for both strong and weak atom-vacuum-field coupling. By solving it numerically, we demonstrate the inapplicability of weak-coupling-based van der Waals interaction models in a close vicinity of the nanotube surface.

Orientational order of surfactant micelles and proteins on crystalline templates has been observed but, given that the template unit cell is significantly smaller than the characteristic size of the adsorbate, this order cannot be attributed to lattice epitaxy. We interpret the template-directed orientation of rodlike molecular assemblies as arising from anisotropic van der Waals interactions b...

Accurate calculations of adsorption energies of cyclic molecules are of key importance in investigations of, e.g., hydrodesulfurization (HDS) catalysis. The present density functional theory (DFT) study of a set of important reactants, products, and inhibitors in HDS catalysis demonstrates that van der Waals interactions are essential for binding energies on MoS(2) surfaces and that DFT with a ...

carbon nanotube is investigated based on an elastic multi-layer shell model with van der Waals interaction taken into consideration. The multi-walled carbon nanotube is described as an individual elastic shell and the interlayer friction is negligible between the inner and outer tubes in the proposed model. And the Donnell equations of cylindrical shells are employed to describe the nonlinear b...

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...

The distribution of distances from atoms of a particular element E to a probe atom X (oxygen in most cases), both bonded and intermolecular non-bonded contacts, has been analyzed. In general, the distribution is characterized by a maximum at short E⋯X distances corresponding to chemical bonds, followed by a range of unpopulated distances – the van der Waals gap – and a second maximum at longer ...

Through a study of the van der Waals interaction between a solid and an air-water interface, we investigate the practical and fundamental problem of the limiting height at which an object can approach a free surface. A numerical study of the interface shape reveals dependencies governed by two disparate length scales associated with the relative strengths of the van der Waals and bouyancy force...

We propose a theoretical novel homodimer model of the β- adrenergic receptor (βAR) in complex with a heterogeneous mixture of free fatty acids (FFAs) and cholesterol based on first-principles calculations. We used the density-functional-based tight binding with dispersion (DFTB-D) method, which accurately evaluates van der Waals interactions between FFAs and amino acid residues in the receptor....