[Wien] MINI

[fabella]

Hello,

I'm trying to generate a case.scf that will have forces in order to use 
mini positions.  I've inserted an impurity and still no induced forces, 
i guess this is because i'm using a "fixed" space group with no free 
structure parameters, unlike TiO2.

How do i generate forces from an impurity/vacancy in a typical space 
group like zincblende or diamond?  Am i limited to only those space 
groups with free structure parameters?

How then would you effectively relax an impurity within a typical space 
group structure, will volume optimization suffice?

Thank You much
Wesley