[Wien] antiferroelectric distortion

[arnaud.vasseur at caramail.com]

Dear wien users.

Actually I have a ReO3 cubic, Fm3m structure. With one Re at (0,0,0) and 3 O at (0,0,0.5); (0,0.5,0); (0.5,0,0). I would like to study phase transition from the cubic structure to the tetragonal one. To do this: I optimized c/a (by changing c in the struct file, tetragonal distortion with #sym.op=0) and this has worked well. At this stage I want to do an antiferroelectric displacement of the Re element.
Can you pleas indicate me if this possible?   

Thank you.       

A. vasseur