[lammps-users] about NPT

When I changed to run NVE, the temperature increased from 6e-28 at the beginning to 9e-24 at last, and the pressure was keep constant as -906.21739.

In fact, I just want to relax a cubic sample to achieve required temperature of 300 K and required pressure of 0. According to the comments about fix npt on the lammps website, it should work when I use “fix 1 all npt 300 300 1 xyz 0 0 1 drag 2.2”. Is there any problem with other parameters in my input script file?


Well, you set all the starting velocities to zero instead of giving them a distribution consistent with 300 K. I bet you would see a temperature closer to 300K if you started with a temperature near 300 K. The thermostat can only do so much with a very bad initial condition.