[Wien] optimization

[hazem salem]

Dear Xavier and Stefan,
                                      Thanks for the explanation.
Best wishes
Hazem



________________________________
From: Rocquefelte <Xavier.Rocquefelte at cnrs-imn.fr>
To: A Mailing list for WIEN2k users <wien at zeus.theochem.tuwien.ac.at>
Sent: Monday, January 26, 2009 7:26:03 AM
Subject: Re: [Wien] optimization

Dear Hazem,

When you are doing spin-polarized calculations, it consists to :
- treat correctly the spin state of the magnetic atoms (change in the total energy up to few eV/f.u.)
- treat the long-range magnetic order (change in the total energy by less than 1eV usually - 100 meV ...)

The effect of the long-range order on the atomic structure is negligible. However, the effect of the correct treatment of the spin state (high spin, low spin) of the magnetic atom could be very strong, depending of the nature of the states involved (bonding or antibonding levels). 

Then, usually the less expensive strategy consists to optimize the structure using a spin-polarized calculation based on a ferromagnetic order (no symmetry lowering). 
The total energy of other magnetic orderings could then be deduced using the optimized structure of the ferromagnetic order.

Regards

Xavier Rocquefelte
 
hazem salem a écrit : 
Dear all,
            I have a question about optimizing the lattice constant. If the system is magnetic is it necessary to use spin-polarized calculations for optimizing the lattice constat, or one can do this with a non-spin polarized calculations then use the optimum lattice constant to perform spin-polarized calculations?

Thanks in advance
Hazem


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