using rNEMD method to calculate viscosity for viscous liquids

Dear all:

I am using rNEMD method to calculate viscosity of liquids. I can see that each system is well equilibrated, since the density at specific temperature is close to reference, and the dvx/dz slope is almost linear. But the viscosities I calculated at different temperatures are all in the same magnitude, although at low temperature, the viscosity should be 100 times of the ones at high temperature. Where could be the problem? I have used the same code to calculate the viscosity of water at room temperature, it can make sense. Can I get some hints here? Thanks a lot.



I don't know - have you tried making a measurement on
the same system with NEMD and seeing if the
answer is consistent?