[gmx-users] Potassium ions in OPLS-AA (II)

[David van der Spoel]

On Wed, 2003-06-18 at 16:20, Lieven Buts wrote:
> I have just (re)discovered an updated "ions.itp"
> (posted by David van der Spoel) which defines
> residue types [ NA+ ] and [ K+ ]. These work
> fine, but I still don't understand why the [ K ]
> definition in 3.1.4 ffoplsaa.rtp doesn't work.

Isn't it just because there is no atomtype for K defined in
ffoplsaanb.itp ?


> ions.itp (updated):
> ------------------
> #ifdef _FF_OPLS
> 
> ...
> 
> [ moleculetype ]
> ; molname       nrexcl
> NA+             1
> 
> [ atoms ]
> ; id    at type         res nr  residu name     at name  cg nr  charge  
> mass
> 1       opls_407        1       NA+             NA       1      1      
> 22.98977
> 
> [ moleculetype ]
> ; molname       nrexcl
> K+              1
> 
> [ atoms ]
> ; id    at type         res nr  residu name     at name  cg nr  charge  
> mass
> 1       opls_408        1       K+              K        1      1       
> 39.0983
> 
> ...
> 
> 
> 
> ffoplsaa.rtp (3.1.4):
> --------------------
> ...
> 
> [ NA ]
>  [ atoms ]
>     NA   opls_407   1.000     0 ; Jorgensen ion type would be opls_405
> 
> [ K ]
>  [ atoms ]
>     K    opls_408   1.000     0
> 
> ...
-- 
David van der Spoel <spoel at xray.bmc.uu.se>