[gmx-users] Umbrella sampling

[rose rahmani]

Hi

I use umbrella sampling to calculate PMF, for studying the interaction of
different aminoacids with nanosheet separately. But at the minimum distance
from sheet, potential is zero for all PMF diagrams. I mean there isn't any
positive potential even at closest distance of aminoacid from sheet. I did
pulling and sampling manyyy times with different rates ...,still the same
problem... how could it be possible?What is the problem? I really get
confused. There isn't any closer distance to sample it.
Would you please help me?
With regards

-Rose