[gmx-users] multiple ion species in a single structure.

[Anna Vernon]

dear all

I am struggling to understand why I cannot add several ion species into 
one structure. I want certain numbers of K CL NA ions.

I use the following commands:

gmx genion -s ions.tpr -o x_solv_ions.gro -p topol.top -pname K -nname 
CL -nn 3 -np 2

gmx genion -s ions.tpr -o x_solv_ions.gro -p topol.top -pname MG -np 5

But this does not seem to be the right way of doing it.

I am not sure why this is going wrong... Any help would be greatly 
appreciated. Many thanks in advance!

With  best wishes,

Anna