Hello
I am doing simulations of CNT using lammps. When I use ‘fix nvt’ to to do thermostatting, I could not get a constant value of temperature in thermodynamics data even after long simulation runs. The total energy of the system is more or less constant. But I want the avg kinetic energy to be constant i.e., temperature constant. What could be the reason?.
Regards
APC
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Could be a number of reasons. Without more details it’s impossible
to tell. Can you run NVE and get a stable system with an equilibrated
temperature?
Steve
Hello
For NVE I could get more or less constant total energy, but not temperature.
But what I need is constant temperature, I applied velocity rescaling to obtain constant temperature and got it. But is this correct way to do it?
Is it not possible to obtain constant temperature using NVT?
Regards
APC
Nose/Hoover (fix nvt in LAMMPS), does not mean the
temperature stays exactly fixed every timestep. If that’s
what you want (which you probably really don’t, that’s not
what most people mean by a constant T simulation)
then fix temp/rescale is the way to do it.
Steve
Hello
For NVE I could get more or less constant total energy, but not temperature.
But what I need is constant temperature, I applied velocity rescaling to obtain constant temperature and got it. But is this correct way to do it?
you probably didn't get a fixed temperature.
you only printed it directly after rescaling.
axel.