[Wannier] Question about final spreads

[lan haiping]

Dear All,

I came to confusion about final results of wannierise procedure.
 I am trying to analyse anatase tio2 wannier function and  born charge with
wannier90.x.
I performed 2 calculations with 2 different projection functions sets, other
settings are same. Both reached convergenc (error deltas for total Omega are
about 1E-10). But the total spreads and wannier centers are quite different.
For my first calculation, i just start with sp2 and pz  functions at O
sites, the total spreads finally obtained is 14.397.
While for the second calculation, the projetion functions are s/px/py/pz
functions at O sites,  the total spreads finally obtained is then
15.2170.

The wannier functions of second calculation could be classed into 4 groups
by spreads , while the conclusion is not hold for the fist calculation ( the
wannier functions are then classed into 8 groups ).

According to MV paper, the MLWFs reflect structures'  symmetry by spreads.
So, Both 2 calculations are not correct.

Would you please give me some comments ?
And input files are below :

*num_wann = 16
num_iter = 2000
guiding_centres = T
exclude_bands = 1 2 3 4 5 6 7 8 25 26 27 28 29 30
begin projections
O : sp2
O : pz
end projections
begin atoms_cart
Ti       0.000000000  -0.000000000   0.000000000
Ti       0.000000000   1.892500000   2.378500000
O        0.000000000   0.000000000   1.979863400
O        0.000000000  -0.000000000   7.534136600
O        0.000000000   1.892500000   4.358363400
O        0.000000000   1.892500000   0.398636600
end atoms_cart*

*begin unit_cell_cart
Ang
   1.8925  -1.8925  4.757
   1.8925   1.8925  4.757
  -1.8925  -1.8925  4.757
end unit_cell_cart
mp_grid :  6 6 6
begin kpoints
......
end kpoints*

two final spreads and wannier centers are attached.

*Regards*
Hai-Ping



-- 
Hai-Ping Lan
Department of Electronics ,
Peking University , Bejing, 100871
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 Final State
 WF centre and spread    1  ( -0.057359,  0.368438,  2.144012 )     0.81913203
 WF centre and spread    2  ( -0.057359, -0.368438,  2.144012 )     0.81913201
 WF centre and spread    3  (  0.207447,  0.000000,  1.889906 )     1.06292459
 WF centre and spread    4  ( -0.197679,  0.225730,  7.480939 )     0.95045581
 WF centre and spread    5  ( -0.197683, -0.225729,  7.480937 )     0.95045348
 WF centre and spread    6  (  0.383935,  0.000000,  7.384053 )     0.82485652
 WF centre and spread    7  ( -0.197693,  2.118226,  4.411569 )     0.95044526
 WF centre and spread    8  ( -0.197669,  1.666767,  4.411555 )     0.95046140
 WF centre and spread    9  (  0.383935,  1.892503,  4.508447 )     0.82485530
 WF centre and spread   10  ( -0.057359,  2.260938,  0.234488 )     0.81913205
 WF centre and spread   11  ( -0.057359,  1.524062,  0.234488 )     0.81913192
 WF centre and spread   12  (  0.207447,  1.892500,  0.488594 )     1.06292460
 WF centre and spread   13  ( -0.090800,  0.000000,  1.575406 )     0.88848488
 WF centre and spread   14  (  0.012349,  0.000000,  7.957177 )     0.88317336
 WF centre and spread   15  (  0.012349,  1.892503,  3.935322 )     0.88317159
 WF centre and spread   16  ( -0.090800,  1.892500,  0.803094 )     0.88848495
 Sum of centres and spreads (  0.005703, 15.139999, 57.083998 )    14.39721976
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 Final State
  WF centre and spread    1  (  0.000000,  0.000000,  1.913455 )     1.16247952
  WF centre and spread    2  (  0.000000,  0.000000,  7.509543 )     1.20049037
  WF centre and spread    3  (  0.000000,  1.892500,  4.382956 )     1.20048903
  WF centre and spread    4  (  0.000000,  1.892500,  0.465045 )     1.16247952
  WF centre and spread    5  (  0.000000,  0.000000,  2.004457 )     1.20048828
  WF centre and spread    6  (  0.000000,  0.000000,  7.600545 )     1.16248168
  WF centre and spread    7  (  0.000000,  1.892500,  4.291955 )     1.16248025
  WF centre and spread    8  (  0.000000,  1.892497,  0.374043 )     1.20048827
  WF centre and spread    9  (  0.000000,  0.000000,  1.522196 )     0.75151445
  WF centre and spread   10  (  0.000000,  0.000000,  7.991803 )     0.75151691
  WF centre and spread   11  (  0.000000,  1.892500,  3.900696 )     0.75151511
  WF centre and spread   12  (  0.000000,  1.892501,  0.856304 )     0.75151453
  WF centre and spread   13  (  0.000000,  0.000000,  2.312422 )     0.68819033
  WF centre and spread   14  (  0.000000,  0.000000,  7.201578 )     0.68819219
  WF centre and spread   15  (  0.000000,  1.892500,  4.690922 )     0.68819114
  WF centre and spread   16  (  0.000000,  1.892502,  0.066078 )     0.68819026
  Sum of centres and spreads (  0.000000, 15.139999, 57.083998 )    15.21070184