RESEARCH - SIMULATIONS

Nanocapillary

Consecutive equilibrium configurations of a Lennard-Jones fluid in a nano-capillary with hydrophilic bottom and left walls and hydrophobic top wall opening into a reservoir containing vapour of the same fluid. The x- and y-dimensions are in units of molecular diameters. The pressure in the reservoir is being slowly increased, which results in partial filling of the capillary. The result is obtained from a fully microscopic statistical mechanical model.

Credit: Peter Yatsyshi, Nikos Savva and Serafim Kalliadasis, Department of Chemical Engineering Imperial College London

Molecular dynamics of salt dissolving in water
Ab initio molecular dynamics simulation of sodium chloride dissolving in water. Small blue spheres and big yellow spheres are sodium and chlorine ions, red + white molecules are water. In the course of the simulation, the chlorine ion at the corner leaves the crystal and enters the water. Movie from Michaelides group.
Quantum hydrogen bonds
Quantum hydrogen bonds: We compare the effect of the quantum mechanics of the nuclei on hydrogen bonds with strengths ranging from weak, to intermediate, to strong. An interesting correlation is observed wherein the influence of quantum nuclei on H-bonds depends on their strength: strong H-bonds get stronger and weak H-bonds get weaker. For details of the calculations behind the video, see "Quantum nature of the hydrogen bond", Xin-Zheng Li, Brent Walker and Angelos Michaelides, PNAS, vol. 108, 6369 (2011). Movie from Michaelides group.
Sodium migration in bioactive glass
The mechanism of sodium migration in low-silica alkali-alkaline earth silicate glasses was investigated through Car-Parrinelllo molecular dynamics simulations. The movie shows several consecutive and coordinated hops of sodium cations (highlighted in red) diffusing inside the glass. Atoms of the glass phosphosilicate network are represented as silver chains, Na and Ca cations as spheres. Work from Antonio Tilocca group (TYC@UCL), published in J. Chem. Phys. 2010, 133, 014701.