[gmx-users] lipids crashed

[Albert]

Hello:

I am using c36 FF for a mix lipids simulation which contains 
POPC+20%POPG+10%CHOL. The system was equilibrated for more than 100ns. 
When I add a 3nm vacuum layer in each leaflet, and set compressibility 
to 0 at z direction, many lipids was flipped towards solvent environment 
if I don't restrain the head group of the lipids.

So I am just wondering  how can I solve this problem?

thank you very much.

Albert