Hello,
I’m seeking to model Janus particle with LAMMPS and I have a quick question about setting the force. I’d like to model the particles as being moved by a constant force “forwards”, but that is reoriented in a brownian manner every certain timesteps.
I know that LAMMPS has a couple of commands to set up forces manually, but can this random force be incorporated on LAMMPS? I also had the idea of using a random number generator to determine the force at each timestep before the simulation and making LAMMPS read the value. Is this viable?
Thanks for any help you can give me!
Hello,
I'm seeking to model Janus particle with LAMMPS and I have a quick question
about setting the force. I'd like to model the particles as being moved by
a constant force "forwards", but that is reoriented in a brownian manner
every certain timesteps.
a constant center of mass motion is easily done through fix addforce.
and if i read the documentation of fix langevin right, you could do
the reorientation motion through it via angmom yes. you may need to
experiment with it.
I know that LAMMPS has a couple of commands to set up forces manually, but
can this random force be incorporated on LAMMPS? I also had the idea of
using a random number generator to determine the force at each timestep
before the simulation and making LAMMPS read the value. Is this viable?
that is likely not very efficient. script operations are usually
global and thus not very efficient. if you cannot do it with the
existing fixes, consider writing a custom fix or extending fix
langevin as needed.
axel.
Not clear if your Janus particles are a single
particle or multiple. Either way, you could
write an atom-style variable, that uses a random
number and creates a per-particle force
that is the same for each particle in a molecule
(the big Janus particle), or different for every atom.
Then apply it with fix addforce.
Steve