[gmx-users] non-zero potential in pure POPC bilayer Odd profile across bilayer

[himanshu khandelia]

Hi,

I calculated the electrostatic potential using g_potential across a
large 416-lipid POPC bilayer from a 200 ps trajectory. The bilayer is
well-hydrated, and has zero charge.

However, I get a very odd potential which starts off at 0.0 and ends
at 0.6 V, but is not monotonically increasing all the time. I can
attach a small 8 kb jpg if the admins allow it. Otherwise you might
get an idea of the shape from the diagram below if it turns up right.
The bilayer is between the points 2 and 2. Any tips why this might
happen ?

Thank you very much !

-Himanshu



                                                                  1
                                                                1
                                                              1
                                                           1
                                                         1
                                                       1
                                                     1
               1                                   1
             1  1                                1
           1     1                              1
         1        1                          1
        1           1                    2
1     1              1                 1
  1  1                 1             1
    1                     1         1
                              1    1
                                 2