[gmx-users] ions.itp => no BR- ion defined (FF_Gromos 96)

[Chih-Ying Lin]

Hi
There is no BR- ion defined in ions.itp.
Justin suggested "Proper parameterization is an extensive procedure".

As I checked the FFG53a6nb.itp, there are many sets of parameters
between atoms. I might get the sets of force field parameters for Br-
, something as described by FFG53a6nb.itp.

How to do "Proper parameterization" with a more understandable method?


If the solution is very dilute, Br - ions will have very limited power
affecting the whole system, I suppose. Are there any alternative ways
to solve the problem ?

Thank you
Lin











Chih-Ying Lin wrote:
> Hi
> In the ions.itp, there is no BR- ion defined  (FF_Gromos 96).
>
> But, it was defined in FF_OPLS.
>
> How did people solve the problem?
> Could I simply use all of  BR-atom (assign it a -1 charge) non-bonded
> parameters in FF_Gromos96 instead?
>

No.  Assigning parameters is far more complicated that picking and choosing and
putting them in whatever force field you wish you use.  Proper parameterization
is an extensive procedure.

-Justin

> Thank you
> Lin
> _________________