[Pw_forum] Total Magnetization and Absolute Magnetization

Arles V. Gil Rebaza arvifis at gmail.com
Fri Oct 24 17:46:50 CEST 2014


Dear Arter, this is a old and frecuently asked question. Pleas read the FAQ
section of the QE online manual. Or search in the old mail`s of the QE
forum.
Best

Arles V. Gil Rebaza
Instituto de Física La Plata
La Plata - Argentina

El viernes, 24 de octubre de 2014, Arter, Calvin <arteca9 at wfu.edu> escribió:
> Dear all,
> I was wondering if someone could clear up a question that has been
plaguing me. I have been running spin polarization calculations with QE and
when observing the output files, I notice that during scf iterations the
absolute and total magnetization values don't seem to result from the
values given in the magnetic moment per site area. Intuition would seem to
indicate that the sum of the individual magnetic moments per site would
equal the total magnetization, but this is not the case. Am I misinformed
as to the true definition of these values? Any help would be greatly
appreciated. Attached below is a sample input of mine as well as the output
section in question.
> #########################################################################
> &CONTROL
>     calculation     = 'relax'
>     pseudo_dir      =
'/wfuhs1/thonhauserGrp/arteca9/research/vdW-DF-PC_MOF/pseudo'
>     forc_conv_thr   = 1d-4
>     nstep           = 200
>     tprnfor         = .TRUE.
>     tstress         = .FALSE.
> /
> &SYSTEM
>     ibrav                      =0
>     nat                        =23
>     ntyp                       =4
>     ecutwfc                    =80
>     nspin                      =2,
>     starting_magnetization(1)  =0,
>     starting_magnetization(2)  =0,
>     starting_magnetization(3)  =0,
>     starting_magnetization(4)  =1,
>     occupations='smearing',
>     smearing='gauss',
>     degauss=0.02,
>     input_dft     ='vdw-df-cx'
> /
> &ELECTRONS
>     conv_thr=1d-10
> /
> &IONS
>     ion_dynamics='damp'
> /
> ATOMIC_SPECIES
> C 12.01 C.pbe-mt_fhi.UPF
> O 16 O.pbe-mt_fhi.UPF
> H 1 H.pbe-mt_fhi.UPF
> Li 7 Li.pbe-mt_fhi.UPF
> ATOMIC_POSITIONS (angstrom)
> C        1.453755140   0.012246981  -0.079594812
> C        0.663453062   1.240941667  -0.170078119
> C       19.298189069   1.207986987  -0.233965928
> C       18.546245009  -0.012246981  -0.079594812
> C       19.336547013  13.759058184  -0.170078119
> C        0.701811006  13.792012864  -0.233965928
> C        2.813372710   0.045070532   0.167873909
> C       17.186627290  -0.045070532   0.167873909
> O        3.490725111   1.176551753   0.423550804
> O        3.644284707  14.005389118   0.140162932
> O       16.355714995   0.994611105   0.140162932
> O       16.509274591  13.823448470   0.423550804
> O        1.450093896  12.635140865  -0.339363244
> O       18.549905955   2.364859284  -0.339363244
> H        1.169312072   2.183413428  -0.368693194
> H       18.830688152  12.816586274  -0.368693194
> H        2.866905870   1.840245874   0.765712786
> H        3.105851467  13.214174069  -0.081474394
> H        0.916335384  11.871237496  -0.063772336
> H       19.083664616   3.128762504  -0.063772336
> H       16.894148533   1.785825931  -0.081474394
> H       17.133094130  13.159754126   0.765712786
> Li       0.000000000   0.000000000   1.679283193
>
> K_POINTS {automatic}
>  1 1 1 0 0 0
> CELL_PARAMETERS {angstrom}
> 20.0 0.0 0.0
> 0.0  15.0 0.0
> 0.0  0.0 10.0
> ###########################################################
>  iteration #  3     ecut=    80.00 Ry     beta=0.70
>      Davidson diagonalization with overlap
>      ethr =  2.43E-03,  avg # of iterations =  4.5
>      negative rho (up, down):  1.197E-04 2.084E-05
>      Magnetic moment per site:
>      atom:    1    charge:    0.8656    magn:   -0.0003    constr:
 0.0000
>      atom:    2    charge:    0.8586    magn:    0.0012    constr:
 0.0000
>      atom:    3    charge:    0.8461    magn:    0.0045    constr:
 0.0000
>      atom:    4    charge:    0.8656    magn:   -0.0003    constr:
 0.0000
>      atom:    5    charge:    0.8586    magn:    0.0012    constr:
 0.0000
>      atom:    6    charge:    0.8461    magn:    0.0045    constr:
 0.0000
>      atom:    7    charge:    0.8234    magn:    0.0003    constr:
 0.0000
>      atom:    8    charge:    0.8234    magn:    0.0003    constr:
 0.0000
>      atom:    9    charge:    1.9314    magn:    0.0006    constr:
 0.0000
>      atom:   10    charge:    1.9316    magn:    0.0000    constr:
 0.0000
>      atom:   11    charge:    1.9316    magn:    0.0000    constr:
 0.0000
>      atom:   12    charge:    1.9314    magn:    0.0006    constr:
 0.0000
>      atom:   13    charge:    1.9380    magn:    0.0006    constr:
 0.0000
>      atom:   14    charge:    1.9380    magn:    0.0006    constr:
 0.0000
>      atom:   15    charge:    0.3818    magn:    0.0002    constr:
 0.0000
>      atom:   16    charge:    0.3818    magn:    0.0002    constr:
 0.0000
>      atom:   17    charge:    0.3907    magn:    0.0003    constr:
 0.0000
>      atom:   18    charge:    0.3795    magn:    0.0001    constr:
 0.0000
>      atom:   19    charge:    0.3896    magn:    0.0002    constr:
 0.0000
>      atom:   20    charge:    0.3896    magn:    0.0002    constr:
 0.0000
>      atom:   21    charge:    0.3795    magn:    0.0001    constr:
 0.0000
>      atom:   22    charge:    0.3907    magn:    0.0003    constr:
 0.0000
>      atom:   23    charge:    0.1843    magn:    0.0238    constr:
 0.0000
>      total cpu time spent up to now is      468.8 secs
>      total energy              =    -292.75808532 Ry
>      Harris-Foulkes estimate   =    -292.87937615 Ry
>      estimated scf accuracy    <       0.26666067 Ry
>      total magnetization       =     0.29 Bohr mag/cell
>      absolute magnetization    =     0.32 Bohr mag/cell
> ###############################################################
> --
>
> Calvin Arter
>
> Wake Forest University
>
> B.S. in Physics and B.A. in Philosophy

-- 
###--------->   Arles V.   <---------###
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