[gmx-users] where is the position of the partial charges?

[Chris Neale]

Hi Lin,

The position of the partial charge is at the center of the atom (the "atom" is really only a point on which the functions are centered). 
If you want to change the position of the partial charge then you need to create another atom to carry that charge. Something like this is
done with Tip4P and Tip5P water molecules in order to separate the LJ and coulombic components. In the case of Tip4P, the oxygen carries mass, bond, 
angle, and LJ components, and the MW "atom" carries the charge of the oxygen. In this case, MW is a dummy atom. You can see how that is done
 in tip4p.itp.

Chris.


-- original message --

Hi
where is the position of the partial charges?

Is it in the center of the atom?


As one user of Gromacs, I can assign or write the partial chage for
each atom in the .top file.

How about changing the position of the partial charge?

Thanks
Lin