A novel way to calculate the diffusivity of water in carbon nanotubes

Theoretical studies on water diffusion in carbon nanotubes have been challenged because the diffusivities calculated by molecular simulations are much lower than what experiments show. This paper proposes a new way to estimate transport diffusivity in such systems directly by simply inspecting the long term behaviors of the velocity autocorrelation functions of water molecules. The results from simulation of molecular dynamics based on this method show that the new method can generate much higher diffusivities, in accordance with experimental measurements, and of the correct order of magnitude.