Re: [NAMD] Apply an electric field only in a specific region

From: The Cromicus Productions (
Date: Tue Jun 19 2018 - 03:41:15 CDT

Thanks for the reply! I've been reading about that function and it does
seem to be able to do what I want.
I have one small question, concerning the part where it says:
*mgridforcechargecol *[image: $ <$] tag [image: $ >$] [image: $ <$] column
of PDB from which to read atom charges [image: $ >$]
*Acceptable Values: *X, Y, Z, O, or B
*Default Value: *Atom charge used for electrostatics.
*Description: *Which column in the PDB file specified by
mgridforcefile contains
the atom charge. By default, the charge value specified for the short-range
Columb interactions are also used for the grid force. Both mgridforcecol and
 mgridforceqcol can be specified, in which case the apparent charge of the
atom will be the product of the two values.

What do they mean with "by default"? If I want to use the charge from the
psf files do I just put "1" on whichever column I choose (for example, B)?
Or do I have to put those charges in B?


On Mon, Jun 4, 2018 at 7:33 AM, Giacomo Fiorin <>

> Hi Sebastian, take a look at the mGridForce and related commands.
> Giacomo

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