[lammps-users] fix rigid and fix nvt

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1

Hi Everyone,

I am trying to simulate a coarse grained system where I fixed several atoms (fixed atoms are free to rotate and translate as a unit) and I attached floppy polymers to these fixed atoms.
I used "fix rigid" command for fixed atoms and "fix nvt" for floppy part because I want to control the temperature. When I used both fixes, LAMMPS time integrates twice as it is indicated in the warning message. When I remove "fix nvt", I cannot control the temperature.
My question is :
Is there a way to control temperature while using "fix rigid" command ?

Thanks in advance,
-burak

2

You should be able to use fix rigid for one set
of atoms and fix nvt on another set. If the sets
don't overlap then you won't get that warning/error.

This is a reasonable way to thermostat the rigid
particles (i.e. by collisions with free thermostatted
particles). Or you can use fix langevin on the atoms
in rigid bodies, which typically works OK.

Steve