Velocity Command

I'm having trouble with the velocity zero linear zero angular command. It destroys my cluster because it seems to add too much velocity. My data shows that the command adds velocity. The sum of all the velocities should be 0, but individual atoms do gain velocity by the end of the simulation. How can I control how much velocity it adds? Or is there another command I can use to add velocity to each individual atom without changing the overall momentum? This one seemed good but it destroys my cluster.

I'm having trouble with the velocity zero linear zero angular command. It destroys my cluster because it seems to add too much velocity.

My data shows that the command adds velocity. The sum of all the velocities should be 0, but individual atoms do gain velocity by the end
of the simulation. How can I control how much velocity it adds?

according to the input you posted earlier, this velocity is not added
due to the command, but due to very bad energy conservation of your
time integration. if i remember correctly, you had a huge time step.
that cannot work.

Or is there another command I can use to add velocity to each individual atom without changing the overall momentum? This one seemed
good but it destroys my cluster.

as i said in a previous reply. there is no velocity added through the
command you used. the velocity command only acts immediately. if you
see velocity being added to your system, it is due to bad energy
conservation. have a look at previous discussions on this subject here
on the mailing list, and check out the discussion of how to choose a
suitable time step for an MD simulation in your favorite MD text book.

axel.