[gmx-users] CHELPG charges from gamess very large

[Anton Feenstra]

Lakshmi Padmavathi wrote:
> Dear gromacs users,
> i calculated the CHELPG charges by using GAMESS for a molecule which contains 
> megnesium. but the charges are very large. for example, MG has 10.000 
> charge.i used STO as basis set.

If that is 10000 e it is bogus. Don't use them.

> can I use these charges for the gromacs directly or am i need to preprocess by 
> any package.
> 
> As i understood from the gromacs user archive,many of you used GAMESS to 
> create partial charges.  i will be very thankful to you if anyone can give 
> the suggestion.

Ab initio or semiempyrical charges are not used directly in the Gromos force-
fields. In stead, they are adjusted to give experimental Dhvap, density, mixing
properties etc. There is no package to do this (although there are tools that
do an automated optimization of parameters to give certain 'target' properties)


-- 
Groetjes,

Anton
  _____________ _______________________________________________________
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|  _   _  ___,| K. Anton Feenstra                                     |
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