Recent multicolor photon-echo experiments revealed a long-lasting quantum coherence between excitations on the donor and acceptor in photosynthetic systems. Identifying the origin of the quantum coherence is essential to fully understand photosynthesis. Here we present a generic model in which a strong intermolecular steric restoring force in densely packed pigment-protein complexes results in ...

We study the stability of a finite-length fluid rivulet at rest on a partially wetting surface. We consider the problem by including the intermolecular force (van der Waals interaction) within the framework of the lubrication approximation. The results are validated by comparison with numerical simulations of the full nonlinear equation. For finite length rivulets, we show that the distance bet...

The isolation of single polyelectrolyte chains of water-soluble poly(isocyanodipeptide)s (PICs) bearing carboxylic acid terminated side chains occurring both at surfaces and in solution was accomplished by reducing the intermolecular interactions through complexation with cations or positively charged surfactants. Scanning force microscopy and viscosity analyses revealed that this method allows...

We study the formation of capillary bridges between micrometer-sized glass spheres immersed in a binary liquid mixture using bright field and confocal microscopy. The bridges form upon heating due to the preferential wetting of the hydrophilic glass surface by the water-rich phase. If the system is cooled below the demixing temperature, the bridges disappear within a few seconds by intermolecul...

The interpretation of physico-chemical observables in terms of atomic motions is one of the primary objectives of atomistic simulations. Trajectories from a molecular simulation contain much valuable information about the relationship between motion of the atoms and physical observables related to them, provided that the interactions used to generate the trajectories are of sufficiently high qu...

Scanning probe microscopy can be used to probe the internal atomic structure of flat organic molecules. This technique requires an unreactive tip and has, until now, been demonstrated only at liquid helium and liquid nitrogen temperatures. We demonstrate intramolecular and intermolecular force contrast at room temperature on PTCDA molecules adsorbed on a Ag/Si(111)-(√[3]×√[3]) surface. The osci...

The potentials of mean force between sodium and chloride ions and between sodium and dimethylphosphate ions in aqueous solution are calculated by the probability ratio method using adaptive umbrella sampling Monte Carlo with a variety of simulation setups. The potential of mean force of sodium chloride is found to have only one minimum in contradiction to earlier molecular dynamics results with...

Pentamer cluster of azodicarbonamide (ADA) based on the crystalline structure was investigated for the equilibrium structure, the stabilization energies, and the vibrational properties at various levels of the density functional theory. Stretching force constants of N...H or O...H, and angle-bending force constants of N-H...N or N-H...O for intermolecular hydrogen bonds in the pentamer cluster ...