[gmx-users] adding potassium

[Magnus Andersson]

Hi,

I'm having a problem adding potassium. I added this ion to the following
files:

ions.itp
ffG43a1.rtp
ffG43a1.atp

and pdb2gmx worked fine. Also creating a box & solvation worked. When I
run grompp though, the following error message comes up:

WARNING 1 [file em.mdp, line unknown]:
  Unknown left-hand deltagrid in parameter file

checking input for internal consistency...
calling /lib/cpp...
processing topology...
Generated 279 of the 1225 non-bonded parameter combinations
Cleaning up temporary file gromppZHe8Zw
Fatal error: Atomtype 'K+' not found!

So it seems like I have to add potassium somewhere lese as well...

Anyone knows where?

Greetings / Magnus Andersson