Mean residence time of co₂ molecules in flexible zif-8 cages explored by molecular dynamics simulations

The adsorption sites and diffusion mechanism of CO₂ molecules in the flexible Zn(MeIM)₂ (MeIM=2-methylimidazole) (ZIF-8) have been investigated by grand canonical Monte Carlo and molecular dynamics simulations. A reasonable time correlation function is for the first time constructed to explore the mean residence time of CO₂ molecules in the ZIF-8 cages, suggesting that CO₂ molecules can remain in the same cage for up to several tens of picoseconds. Furthermore, we find that the mean residence time almost linearly increases with the increasing pressure (or loading) at 273 and 298 K.