A novel algorithm was described that included the effect of host-lattice flexibility upon molecular dynamics simulations that used rigid lattices. A Lowe-Andersen thermostat was used 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 explicit simulation. A study was made of the influence of flexibility upon the self-diffusion of simple gases within single-walled carbon nanotubes. Results were shown for various guest molecules (methane, helium, and sulfur hexafluoride), temperatures and types of carbon nanotube. It was shown that, at low loadings, flexibility was always relevant. It had a notable 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. Jakobtorweihen, S., Lowe, C.P., Keil, F.J., Smit, B.: Journal of Chemical Physics, 2006, 124[15], 154706