[Pw_forum] Differing bond lengths from relax calculation

[Izaak Williamson]

Dear members,

I am running a relax calculation on trimers of the type M-N-M where M describes 
a magnetic atom. I am running them as spin-polarized calculations with 
Hubbard-U. The shape of the unit cell is cubic. I want to find out the 
equilibrium bond length (M-N). Since the cluster is symmetric, I would expect 
that both M-N-M bond lengths would be same. But, it turns out that two bond 
lengths are different. Why is this happening? Any help would be much 
appreciated.

Thanks for any help,

Izaak Williamson
Research Assistant
Physics Department
Boise State University


      
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