hole in confined fluid

Dear LAMMPS users,

I have simulate a fluid confined in graphene . Plates of graphene align in the direction of x and y , and The periodic boundary condition is applied in two directions other than the fixed wall)(graphene) direction. I maintain a constant pressure P = 1 along the periodic boundary directions.
When the system runs , in the fluid a hole is formed. anybody knows what is the cause?

Dear LAMMPS users,

I have simulate a fluid confined in graphene . Plates of graphene align in
the direction of x and y , and The periodic boundary condition is applied in
two directions other than the fixed wall)(graphene) direction. I maintain a
constant pressure P = 1 along the periodic boundary directions.

When the system runs , in the fluid a hole is formed. anybody knows what is
the cause?

not without a crystal ball.

most likely, you are doing something wrong.

axel.

Dear LAMMPS users,

I have simulate a fluid confined in graphene . Plates of graphene align
in
the direction of x and y , and The periodic boundary condition is applied
in
two directions other than the fixed wall)(graphene) direction. I maintain
a
constant pressure P = 1 along the periodic boundary directions.

When the system runs , in the fluid a hole is formed. anybody knows what
is
the cause?

not without a crystal ball.

most likely, you are doing something wrong.

Or it's the discovery of a new phenomenon...

No it is not. Assuming that all FF parameters are correct and no typo lives in the input deck her hole is showing nothing but a problem with her equilibration procedure. A pressure (force) has to be applied to the graphene plates otherwise one cannot really claim this is a fluid confined between walls. In this case is better to freeze one plate, keep the second one mobile and apply a force along z on each atom so that one can ensure the confinement of the fluid. If interested in low-pressure equilibrium configs, it is better to start applying plate forces that correspond to much higher pressures. This generally speeds up the convergence. Next, one decreases the pressure/force on the plate to the desired value and wait again for equilibration. Make sure as well there are enough fluid units (atoms or molecules) to properly mimic the liquid.
Carlos

Please have also a look at this very similar thread:

http://lammps.sandia.gov/threads/msg43648.html

2014-01-29 Carlos Campana <[email protected]>: