[gmx-users] Warning when using both LJ and Buckingham non-bonded interaction

[Mark Abraham]

WU Yanbin wrote:
> Hi,
>   When I use both LJ and Buckingham non-bonded interaction in my 
> topology file, specially like the following:
>   --------------------------------
>       [ nonbond_params ]
>         ; i    j         func          c6           c12
>          OW   OW   1  ...
>         ; i    j       func           a             b            c6
>           C    C    2  ...
>   --------------------------------
> 
>   When I run grompp using this topology file, I got such message:
>   --------------------------------
>         WARNING 2 [file "topol.top", line 26]:
>         Trying to add BuckingHam while the default nonbond type is LJ (SR)
>   --------------------------------
>  
>   Then is this topology OK? or I need other modifications?

What single force field requires you to need to do this?

There's no numerical problem, but the warning is there because you 
probably have an inappropriate model for your system.

Mark