units of pressure and velocity gradient

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1

Dear All,
When I use the SLLOD equations of motion to evaluate the viscosity of ionic liquids, I get values that are about a hundred times higher than experimental values and values obtained from equilibrium Green-Kubo relations using Gromacs. Otherwise the qualitative functional dependence of the viscosity on the shear rate seems to be reasonable. Therefore, I wonder whether I use the wrong units for the pressure or the velocity gradient. I use the option "units real" where the pressure unit is atmospheres and the time unit is femtoseconds, so that the unit of the velocity gradient ought to be 1/femtoseconds. The results would be much more reasonable if the pressure unit was kPa.

Best Regards,

Sten Sarman

2

You are correct that pressure is in atm and time is in fs. There must be something in your simulation or in your script that is causing the discrepancy.

Ray