Hi!

I am trying to calculate the diffusivity of water in the presence of carbon nanotubes using the Discover module and the SPC model for water. I have constrained the bond length of water using the rattle option available in Discover but I am getting some undesirable results. The values for the MSD of water are very small and, indeed, when I analyze the frames in the trajectory, I see that water molecules seem not to move, they just oscillate around their starting positions and as a result, water is not diffusing.

Can anyone give me a hand?

Thanks in advance!

Regards

Isabel