Force Field for Molecular Dynamics Computations in Flexible ZIF-8 Framework

Correct modeling of framework flexibility plays a major role in obtaining accurate results when performing atomistic simulations of guest molecule diffusion within ZIF crystal structures. Here we present a full set of force field parameters, based on the AMBER database and on previously computed partial charges, well reproducing the ZIF-8 structural properties over a wide range of temperatures and pressures. To test our model, the self-diffusivity for sorbed carbon-dioxide is computed and is found to be in good agreement with experimental measurements. Our results are also compared to the ones obtained with other charge models and are found to be more accurate. Finally, an estimate of the influence on self-diffusion of various simulation details is given.