From: Mayne, Christopher G (
Date: Wed Apr 17 2013 - 09:52:43 CDT

I don't think so. The optimizer judges the ability of a charge set to reproduce the interaction, but the positioning of the water is predetermined based on geometry, i.e., not a stochastic calculation. The best time to modify your weights is when you want to bias the charge sets towards getting a particular interaction correct (relative to qm).

On Apr 17, 2013, at 9:18 AM, "Wenhao Liu" <<>> wrote:

So you mean I can set the weight like to 2 when I deal with oxygen-water bonding in the condition that oxygen in my new molecule can form two hydrogen bonds with water? Thank you!


$B:_(B 2013$BG/(B4$B7n(B17$BF|@14|;0!$(BMayne, Christopher G $B<LF;!'(B
It is not required due to the symmetry of water--there is no extra information to be gained by flipping the identities of the hydrogens. ffTK handles the positioning of the water automatically.

Christopher Mayne

On Apr 17, 2013, at 1:53 AM, Wenhao Liu wrote:

> Hello vmd people,
> I was just wondering is it required to set up more than 1 hydrogen bonding for Acceptor (like the oxygen that can bonding with 2 hydrogen of the water) when I need to do the water interaction Gaussian calculation in charge optimization step? But I can only have 1 possible conformation to put water molecule bonding with oxygen in Acceptor indices, the other possible hydrogen boding between oxygen and hydrogen of water should be in different orientation, right? Or I can just set the weight of this calculation to 2 when I do the charge optimization? Thanks in advance.
> Wenhao