[lammps-users] fix nvt command

Hi Steve,

I just want to confirm if my understanding of an integrator such fix nve
or nvt is correct. If I have a charged substrate that doesn't move, I have
to set initial velocity of the substrate atoms equal to zero and use fix
setforce zero for all substrate atoms. And, I have polymers that are
flowing. Hence I have two groups, substrate and polymer.

Is it correct that I don't need to integrate the substrate group? So, I
could just use "fix 1 polymers nvt 300.0 300.0 100.0" instead of fix 1 all
nvt 300.0 300.0 100.0". The pairwise interaction between the substrate and
polymers are still evaluated, right? Is there a performance benefit of
just integrating the polymers?


yes, if you integrate them all then you need to insure
v and f are zero - or you could just not integrate
the immobile atoms