[gmx-users] How to control the temperature when using an electric field?

[Apoorv Kalyankar]

In GROMACS, I believe that whenever an external force is applied, the
mean velocity of the group is subtracted before rescaling the
velocities and then the mean velocity is added back in. So if you are
expecting  a plug like flow then there should not be any problem. In
other cases also, it should not create a problem since your external
electric field is not that large.

And yes you should not remove the center of mass motion of the
molecules otherwise you will get zero velocity.

Apoorv

On Fri, Apr 22, 2011 at 2:09 AM, lammps lammps <lammp2forum at gmail.com> wrote:
> Hi,
>
> I want to use the option of E_x = 1   0.01  0 to add an electric field to
> the simulated system in NVT ensemble.
>
> Because there should exist an no zero velocity of center-of-mass in the x
> direction. It seems that it is wrong to directly use the nose-hoover to
> control the temperature.
>
> it is also not reasonable to use nstcomm   = 1, because the velocity of
> center-of mass in the x-axis should be kept when runing.
>
> So, How to control the temperature? When calcating the temperature in the
> process of simulations, how to exclude the velocity of center-of-mass of x
> direction for controling the right T?
>
> Thanks in advance.
>
> --
> wade
>
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