[gmx-users] Chloride parameters in ffgmx

[Anton Feenstra]

hugo verli wrote:
> Hi,
> 
[...]

> The charges were obtained from Ab-initio calculations and the topology for the
> chloroform made in PRODRG site.
> 
> Any suggestion? Could this error be due to atomic charges or to van der Waals
> parameters (form chloride ion and not for covalent bound chlorine)?
[...]

There is already chloroform in the Gromos forcefield, isn't it also
already in the Gromacs? If not, you could probably simply take the
Gromos parameters, at least for a good start.

Ab-initio charges are usually (a lot) higher than those used in the
Gromos/Gromacs forcefields, for example, from page IV-271 GromOS
manual, Cl charges are -0.087, C is 0.179 and H is 0.08. You can
compare these to the charges you found from Ab-initio.

-- 
Groetjes,

Anton
  _____________ _______________________________________________________
|             |                                                       |
|  _   _  ___,| K. Anton Feenstra                                     |
| / \ / \'| | | Dept. of Pharmacochem. - Vrije Universiteit Amsterdam |
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