[gmx-users] Re: charges

[hugo verli]

And about the Lowdin charges? 
I read that it gives charges less intense than that produced by mulliken
population analysis. Wouldn't it be of interest in the simulation of hypervalent
groups?

Hugo Verli.

> Christoph Freudenberger wrote:
> 
> > Erik Lindahl wrote:
> >
> >> The nice thing with gaussian is that newer versions allow you to just
> 
> >> enter a set cartesian coordinates and the number of electrons for 
> >> each atom, and then it can either optimize the structure or just 
> >> derive partial charges (e.g. with CHELPG).
> >
> > The standart method of gaussian for calculating charges (Mulliken) is
> > known to be quite bad.
> > Which one should be used to produce relieable results for MD?
> 
> CHELPG is stable and good to very good even for large molecules. 
> Merz-Kollman  might be slightly better for small molecules,
> but it is reported to be much more sensitive to the conformation, so it
> 
> can be unstable for large molecules.
> 
> For the single Gaussian run I've done I used CHELPG, simply because it's
> 
> the suggested standard in OPLS, and my molecules were large (lipids).
> 
> You select the method to use with pop=chelpg or pop=mk
> 
> Cheers,
> 
> Erik
> 
> 
> 
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