Dear Pavel,

   at a first glance, it looks to me that your degauss is to large and the 
k-point sampling insufficient for magnetic calculations. This said, I don't 
understand why you get such a strange solution. With your initial choice of the 
angles you might be forcing some symmetry that prevents from reaching the 
ground state. Nevertheless, if you start from a magnetic configuration very far 
from the ground state you might get trapped in some local minima even with the 
correct symmetry, I suppose. 

Beware that starting_magnetization should be between -1 and 1, see 
Doc/INPUT_PW.txt. 
I remember that Paolo put some checks at some point. Which version of the code 
are you using?

Finally, unless you include spin-orbit coupling or you consider situations with 
frustrated magnetism there is no need of using the noncollinear scheme.

HTH

GS

Il giorno 01/dic/2010, alle ore 02.49, Lukashev Pavel ha scritto:

> Dear All,
> 
> I am running a test calculation of bcc iron, to check if the relaxation of 
> angle1 (theta) works correct for the non-collinear case. I have copied the 
> file "fe.pen.in" from the examples provided on pwscf.org, and added one more 
> Fe atom (so, I have two Fe atom unit cell). I set angle1(1)=90;  
> angle1(2)=0.0. After self-consistent calculation I expect these angles to be 
> aligned (ferromagnetically). Yet, I end up getting very strange result, i.e. 
> theta(1)=70.356498; theta(2)=19.684944. Does this mean that the relaxation of 
> atomic magnetic moments is not very reliable in case of non-collinear 
> calculation? This is first time I am trying to include non-collinearity in my 
> calculation, therefore I don't have much to compare with. And I did not find 
> any published work on non-collinear systems done with PWSCF. Any help on this 
> issue is very appreciated. I attach my input file which also includes portion 
> from output showing magnetization magnitude/direction.
> 
> Sincerely,
> 
> Pavel Lukashev, Ph.D.
> Research Associate
> UNL, Department of Physics & Astronomy
> 208 Theodore Jorgensen Hall
> 855 N. 16th Street
> Lincoln, NE 68588-0299
> Office: (402) 472-2400
> <Fe-noncollinear.txt>_______________________________________________
> Pw_forum mailing list
> Pw_forum at pwscf.org
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? Gabriele Sclauzero, EPFL SB ITP CSEA
   PH H2 462, Station 3, CH-1015 Lausanne

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