A novel algorithm was described which incorporated the effect of host-lattice flexibility into molecular dynamics simulations that assumed rigid lattices. It used a Lowe-Andersen thermostat for interface-fluid collisions in order to take the most important aspects of flexibility into account. The same diffusivities and other properties of the flexible framework system were reproduced at a small fraction of the computational cost of an explicit simulation. The influence of flexibility upon the self-diffusion of simple gases inside single-walled carbon nanotubes was studied. Results were presented for various guest molecules (methane, helium, sulfur hexafluoride), temperatures, and types of carbon nanotube. It was show that, at low loadings, flexibility was always relevant. In particular, it had a crucial influence upon the diffusive dynamics of the guest molecules.

A Novel Algorithm to Model the Influence of Host Lattice Flexibility in Molecular Dynamics Simulations: Loading Dependence of Self-Diffusion in Carbon Nanotubes. S.Jakobtorweihen, C.P.Lowe, F.J.Keil, B.Smit: Journal of Chemical Physics, 2006, 124[15], 154706