I’ve found a post concerning “Constant area simulations with lammps” (http://lammps.sandia.gov/threads/msg30742.html).
Can’t we make fluctuating area by having xy coupled in npt ensemble?
Like people used to do for a lipid membrane simulations (ex. Biophisical Journal 92, 147-161, 2007)? In my lammps file I have eg.:
fix 2 copol npt temp {T} {T} 100.0 x {p} {p} 500.0 y {p} {p} 500.0 z {p} {p} 500.0 couple xy
and a cross area is fluctuating around a constant value.
My question is rather how to implemented in LAMMPS a simulations with constant x, constant y and fluctuating z for a given pressure. In the post I have mentioned, there is that: fix 1 all npt temp 300 300 100 z 500 500 1000.0 will have z fluctuating and x constant and y constant. But I do not know how these x and y values are established? The only way that comes to me now, is that I will need to have nvt ensemble with established x, y, and z and then switch to this npt (fix 1 all npt temp 300 300 100 z 500 500 1000.0), but it sounds little bit awkward…
Could you tell me how to do the simulations where you have constant x, constant y and fluctuating z so the pressure is constant?
Regards,
Goska Kowalik