[Pw_forum] Constrained Direction of Magnetization

[Sahar Mirshamsi]

Hi pwscf users,

I am trying to do non-collinear calculation and add a penalty functional
to the Hamiltonian in order to constrain direction of magnetic moment of
some atoms in my desired direction. So I added these tags to my usual
input file:

noncolin=.TRUE.
constrained_magnetization='atomic'
angle1(i)= desired amount in degree    i=1,ntyp
angle2(i)= desired amount in degree    i=1,ntyp
lambda=desired amount

as the result, I expect that the code will keep the direction of magnetic
moments in desired direction and in every step just changes the magnitude
of magnetization until the convergence achieves, but I see the magnetic
moment of every atom is changing in both magnitude and direction in every
step.

1) Am I missing something in my input file? or the whole procedure is
different from what I expected?
2) How starting_magnetization will be related to this constraining
process?
3) How does code choose the radius of the sphere around every atom for
calculating the charge and magnetic moment of every atom?

I appreciate any help in finding the answers of these questions.

______________________________
Sahar Mirshamsi
Quantum Theory Project (QTP) and Physics Department,
University of Florida