[gmx-users] Umbrella saming

[rose rahmani]

I do umbrella sampling for different distances of AA perpendicular to
nanotube axis. Imagine nanotube is along Y axis and i want to pull AA along
just Z axis. But during pulling (i mean most of the time) it trapped in X
axis and pulls along x axis.
I used pull_vec= 0 0 1 and pull_geometry= direction, force constant= 5000 .
How can i make it to move just along Z axis?
Would you please help me?

Best regards
-Rose