Hi all,
I simulated a periodic box including a graphene sheet at the middle (Fig. is attached). I did some NPT dynamics under the atmosphere pressure, but the length of the box didn't reduced in C direction (normal to graphene). This also happens when some polymer chains are packed into the empty space of the box with low density (e.g. 0.5 g/cm3). What is the reason?

Thank you in advance.
Farzin
I simulated a periodic box including a graphene sheet at the middle (Fig. is attached). I did some NPT dynamics under the atmosphere pressure, but the length of the box didn't reduced in C direction (normal to graphene). This also happens when some polymer chains are packed into the empty space of the box with low density (e.g. 0.5 g/cm3). What is the reason?
Thank you in advance.
Farzin