[lammps-users] huge Increasment of volume of box using fix npt

Hi,
I am working with npt ensemble on SiC crystal.I set pressure zero and temperature 700K(fix 1 all npt 700 700 50 aniso 0.0 0.0 0.0 0.0 0.0 0.0 300 drag 2.0).My timestep is 1fs.When I run 15000 timesteps,the volume of the box is 200 times larger of the inital crystal box,also the system becomes amorphous.The melting point of SiC is much higher than 1000K.I don’t know what’s wrong with my simulation.
Thanks for any feedback!

Jim

What units are you using? And what is the initial pressure at time 0?

Steve

2009/12/13 dragon <[email protected]>: