[SIESTA-L] Problem with lattice parameter of Cr

[fatah chiter]

Dear all,
I have something unclear with lattice parameter of GGA Siesta calculation on
Body centered Cr.
Calculation without SpinPolarized gives  lattice parameter a=2.89  Angstrom.
The experimental value is a=2.88.
Same calculation with  "SpinPolarized= True" gives a=3.94  Angstrom which is
very differnt from 2.88.
Could anyone tell me where i am wrong?  Thank you