[gmx-users] monolayer and ensembles

[Ramon Reigada]

Dear users of GROMACS,

   two days ago I sent a question related to the appropriate procedure 
to simulate lipid monolayers, keeping both the normal pressure and the 
surface x,y area constant (instead of the constant normal pressure and
constant surface tension algorithm that is implemented in GROMACS).
Andre Farias de Moura kindly answer my question, but we still have some 
doubts about constructing the monolayer.

The procedure I am thinking to built the initial configuration of the 
monolayer is the following. We place the lipids above a water slab, and 
below the water slab and above the lipid array, some vacuum is left.
Then, we want to keep a constant normal pressure (so, z-box will vary) 
and a constant surface (x,y)-area (so, surface tension will vary).
Andre (and other gromacs users), is this the correct way to built a 
langmuir monolayer? is my proposed ensemble NPAT equivalent to your 
proposed NVT ensemble? these are my two questions.

   thank you very much,

     RAMON REIGADA