[gmx-users] Details about using g_wham

[Yoo Chan Myung]

Dear GMX-Users,

I’m trying to obtain free energy profile of small molecule penetration
through POPC membrane.

To do that, many researchers simulate using Umbrella Sampling with G_Wham
analysis.

(Reference : 'convergence of free energy profile of coumarin in lipid
bilayer’, Michal Otypeka)


Most of x-axis(Distance from the middle of the lipid bilayer) of free
energy profile show minus to plus x-axis.

In my case, I have no idea how to obtain the g_wham results with region
from minus to plus of membrane(x-axis).
($ g_wham -it tpr-files.dat -if pullf-files.dat -o -hist -unit kCal)

I always get an energy profile which is raged from 0 to 3 for x-axis, not
in minus.

Is there any options on g_wham?

Many thanks,

Yoochan