BACKGROUND The response of molecular crystal structures to changes in externally applied conditions such as temperature and pressure are the result of a complex balance between strong intramolecular bonding, medium strength intermolecular interactions such as hydrogen bonds, and weaker intermolecular van der Waals contacts. At high pressure the additional thermodynamic requirement to fill space...

Critical to biological processes such as membrane fusion and secretion, ion-lipid interactions at the membrane-water interface still raise many unanswered questions. Using reconstituted phosphatidylcholine membranes, we confirm here that multilamellar vesicles swell in salt solutions, a direct indication that salt modifies the interactions between neighboring membranes. By varying sample histor...

Molecules held together by van der Waals forces generally posess bond strengths which are -0 1-1.0% of normal chemical bonds, i.e. 0.1-1.0 Kcal/mole (.35-350 cmi ). Such extremely weak bonds exhi~it vibrational frequencies which lie in the far-infrared, eq. 10-100 cm(1000-100 11m). In order to measure vibration-rotation spectra of van der Waals bonds, one must devise a method which possesses ve...

The computer program DOT quickly finds low-energy docked structures for two proteins by performing a systematic search over six degrees of freedom. A novel feature of DOT is its energy function, which is the sum of both a Poisson-Boltzmann electrostatic energy and a van der Waals energy, each represented as a grid-based correlation function. DOT evaluates the energy of interaction for many orie...

Experimental demonstrations of one-dimensional (1D) van der Waals material tellurium (Te) have been presented by Raman spectroscopy under strain and magneto-transport. Raman spectroscopy measurements have been performed under strains along different principle axes. Pronounced strain response along the c-axis is observed due to the strong intrachain covalent bonds, while no strain response is ob...

A series of five uranium-alkane complexes of the general formula [(ArO)3tacn)U(alkane)].(cy-alkane) has been synthesized and crystallographically characterized. In all cases, X-ray diffraction studies revealed a pseudo-six-coordinate trivalent uranium core structure, [(ArO)3tacn)U], with a coordinated alkane ligand at the axial position. The average U-C bond distance to the bound alkane was det...

Recent investigations have shed much light on the nuclear and electronic factors that control the rates of long-range electron tunneling through molecules in aqueous and organic glasses as well as through bonds in donor-bridge-acceptor complexes. Couplings through covalent and hydrogen bonds are much stronger than those across van der Waals gaps, and these differences in coupling between bonded...

The robotic manipulation of microscopic objects is disturbed directly by the adhesion between the endeffector and the objects. In the microscale, no reliable model of adhesion is available and currently the behaviour of the micro-objects cannot be predicted before experiments. This paper proposes a new model of adhesion based on the analytical resolution of the coupling between the mechanical d...

Many naturally occurring microbiological and synthetic polymer systems have soft interfaces due, e.g., to the presence of polymer brushes at the surfaces. The initial interactions (before contact) in such systems are typically physical rather than chemical in origin, e.g. electrostatic or van der Waals forces. We calculate the form of the summed van der Waals interaction energies UHS and USS be...

The energetics of weak interactions (van der Waals forces, hydrogen bonding) are difficult to quantify in biological ligand-receptor pairs. Insight into the biochemical role these forces play is critical to an understanding of signal transduction events and the drug discovery process. Ruthenium pentaammine and iron tetracyano complexes modified with either biotin or desthiobiotin have been synt...