[gmx-users] Re: The molecule size (jiqing)

[Mark Abraham]

主月 ：） wrote:
>  
> 》Has this force field been demonstrated to be effective >for this sort of
>  >simulation? If not, maybe you've begun to demonstrate >that it isn't?
> 
>  >Mark
>  
> Yes , you are quite right. In GMX manual 3.2, at the end of chapter 4, 
> it was said that gromos96 is not, however, recommended for use with long 
> alkanes and lipids.
> So user has to validate force parameters. Now the problem is for a 
> periodic boundary system, the density is ok but the Rg is too small. I 
> feel the parameters for proper dihedrals need to be improved. Is it right?

It's likely that nobody knows.

Find a force field that does work for such simulations, or read
everything you can find on how to build force fields and do it from
scratch. Modifying one sort of parameter is like taking a Beethoven
symphony and substituting the second violin part with bass guitar line
from "Smoke on the Water". It might work, but you'd be mad to bet on it.

Mark