From lanhaiping@gmail.com  Tue Dec  5 18:20:48 2006
From: lanhaiping@gmail.com (lan haiping)
Date: Wed, 6 Dec 2006 02:20:48 +0800
Subject: [Wannier] About Born Charge
Message-ID: <c92002fa0612051020qf60bb2dh9a74fa27db933974@mail.gmail.com>

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Dear Developers ,

 I am wondering about born charge calculation by relative displacement
 Wannier centers.
I tried to repeat this calculation for anatase TiO2 system. Since there are
6 atoms in unit cell, i just displace one of O sites about 0.1% of  cell
lattice along x direction.  I then come to a problem about kpoint setting in
'nscf' calculation of the displacing  case.
With kmesh.sh scripts, i set 4x4x4 kmesh for 'nscf' calculation. When i
tried to run pw2wannier90.x code, calculation failed due to different
kpoints between result of 'nscf' calculation and wannier90 's kmesh setting.
For my case , there are 64 kpoints i set for 'nscf' calculation.Due to
symmetry , the number of kpoints output file gave is 164 kpoints.
 I think there must be some aspects of this calculation scheme i donot catch
much, or understand wrong. Would you please give me some comments ?

Regards.

-- 
Hai-Ping Lan
Department of Electronics ,
Peking University , Bejing, 100871

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<div>Dear Developers ,</div>
<div>&nbsp;</div>
<div>&nbsp;I&nbsp;am wondering about born charge calculation&nbsp;by relative displacement &nbsp;Wannier centers.&nbsp;&nbsp; </div>
<div>I tried to repeat this calculation for anatase TiO2 system.&nbsp;Since there are 6 atoms in unit cell, i just displace one of O sites about 0.1% of&nbsp; cell lattice along x direction.&nbsp; I then come to a problem about kpoint setting in 'nscf' calculation of the displacing &nbsp;case. 
</div>
<div>With kmesh.sh scripts, i set 4x4x4 kmesh for 'nscf' calculation. When i tried to run pw2wannier90.x code, calculation failed due to different kpoints between result of 'nscf' calculation and wannier90 's kmesh setting. For my case , there are 64 kpoints i set for 'nscf' 
calculation.Due to symmetry , the number of kpoints output file gave is 164 kpoints.&nbsp;&nbsp; </div>
<div>&nbsp;I think there must be some aspects of this calculation scheme i donot catch much, or understand wrong. Would you please give me some comments ?</div>
<div>&nbsp;</div>
<div>Regards.<br clear="all"><br>-- <br>Hai-Ping Lan <br>Department of Electronics ,<br>Peking University , Bejing, 100871 </div>

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From wierzbom@ts.infn.it  Wed Dec  6 11:12:54 2006
From: wierzbom@ts.infn.it (Malgorzata Wierzbowska)
Date: Wed, 6 Dec 2006 12:12:54 +0100 (CET)
Subject: [Wannier] About Born Charge
In-Reply-To: <c92002fa0612051020qf60bb2dh9a74fa27db933974@mail.gmail.com>
References: <c92002fa0612051020qf60bb2dh9a74fa27db933974@mail.gmail.com>
Message-ID: <Pine.LNX.4.61.0612061203020.13537@dawn.ts.infn.it>

On Wed, 6 Dec 2006, lan haiping wrote:

   Hi,

> Dear Developers ,
>
> I am wondering about born charge calculation by relative displacement
> Wannier centers.
> I tried to repeat this calculation for anatase TiO2 system. Since there are
> 6 atoms in unit cell, i just displace one of O sites about 0.1% of  cell
> lattice along x direction.  I then come to a problem about kpoint setting in
> 'nscf' calculation of the displacing  case.
> With kmesh.sh scripts, i set 4x4x4 kmesh for 'nscf' calculation. When i
> tried to run pw2wannier90.x code, calculation failed due to different
> kpoints between result of 'nscf' calculation and wannier90 's kmesh setting.

   The k-mesh in nscf for later use in wannier calculations
   has to be given in the whole Brillouin zone and it needs to be uniform.

> For my case , there are 64 kpoints i set for 'nscf' calculation.Due to
> symmetry , the number of kpoints output file gave is 164 kpoints.
> I think there must be some aspects of this calculation scheme i donot catch
> much, or understand wrong. Would you please give me some comments ?
>

   You should not use the symmetry in this case. You cannot use the option
  "authomatic" k-point generation. Instead, in nscf, you should give
  the list of all k-points.

  I know this takes longer for the calculation but at this stage it is done
  like this because we had no time yet to do it better.

  About the number of k-points: It depends on how big is your cell in the
  reciprocal space. If you have some time, you could use 2*2*2=8
  and 4*4*4=64 and 8*8*8=512 and tell us what is the difference
  at the end :-)
  If your cell is cubic you use number of k-points n1=n2=n3, if your cell
  is alongated you should find  such grid with which the distances
  between k-points (in reciprocal space) are almost equal.

  Gosia




From lanhaiping@gmail.com  Mon Dec 18 00:52:23 2006
From: lanhaiping@gmail.com (lan haiping)
Date: Mon, 18 Dec 2006 08:52:23 +0800
Subject: [Wannier] Question about final spreads
Message-ID: <c92002fa0612171652t22c3d215t59410b2d6126332e@mail.gmail.com>

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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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<div>Dear All,</div>
<div>&nbsp;</div>
<div>I came to confusion about final results of wannierise procedure.</div>
<div>&nbsp;I am trying to analyse anatase tio2 wannier function and&nbsp; born charge with wannier90.x. </div>
<div>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.
</div>
<div>For my first calculation, i just start with sp2 and pz&nbsp; functions&nbsp;at O sites, the total spreads finally obtained is 14.397.</div>
<div>While for the second calculation, the projetion functions are s/px/py/pz functions at O sites,&nbsp; the total spreads finally obtained is then </div>
<div>15.2170.</div>
<div>&nbsp;</div>
<div>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 ).</div>
<div>&nbsp;</div>
<div>According to MV paper, the&nbsp;MLWFs reflect structures'&nbsp; symmetry by spreads. So, Both 2 calculations are not correct.</div>
<div>&nbsp;</div>
<div>Would you please give me some comments ? </div>
<div>And input files are below :</div>
<div>
<p><strong>num_wann = 16<br>num_iter = 2000<br>guiding_centres = T<br>exclude_bands = 1 2 3 4 5 6 7 8 25 26 27 28 29 30<br>begin projections<br>O : sp2<br>O : pz<br>end projections<br>begin atoms_cart<br>Ti&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 0.000000000
&nbsp; -0.000000000&nbsp;&nbsp; 0.000000000<br>Ti&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 0.000000000&nbsp;&nbsp; 1.892500000&nbsp;&nbsp; 2.378500000<br>O&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 0.000000000&nbsp;&nbsp; 0.000000000&nbsp;&nbsp; 1.979863400<br>O&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 0.000000000&nbsp; -0.000000000&nbsp;&nbsp; 7.534136600<br>O&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 0.000000000&nbsp;&nbsp; 1.892500000
&nbsp;&nbsp; 4.358363400<br>O&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 0.000000000&nbsp;&nbsp; 1.892500000&nbsp;&nbsp; 0.398636600<br>end atoms_cart</strong></p>
<p><strong>begin unit_cell_cart<br>Ang<br>&nbsp;&nbsp; 1.8925&nbsp; -1.8925&nbsp; 4.757<br>&nbsp;&nbsp; 1.8925&nbsp;&nbsp; 1.8925&nbsp; 4.757<br>&nbsp; -1.8925&nbsp; -1.8925&nbsp; 4.757<br>end unit_cell_cart<br>mp_grid :&nbsp; 6 6 6<br>begin kpoints<br>......<br>end kpoints</strong></p>

<p>two final spreads and wannier centers are attached.</p>
<p><strong>Regards</strong></p></div>
<div>Hai-Ping</div>
<div>&nbsp;</div>
<div><br clear="all"><br>-- <br>Hai-Ping Lan <br>Department of Electronics ,<br>Peking University , Bejing, 100871 </div>

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From marzari@MIT.EDU  Mon Dec 18 02:54:23 2006
From: marzari@MIT.EDU (Nicola Marzari)
Date: Sun, 17 Dec 2006 21:54:23 -0500
Subject: [Wannier] Question about final spreads
In-Reply-To: <c92002fa0612171652t22c3d215t59410b2d6126332e@mail.gmail.com>
References: <c92002fa0612171652t22c3d215t59410b2d6126332e@mail.gmail.com>
Message-ID: <458602DF.4050502@mit.edu>


Dear Hai-Ping,


I believe Michel Posternak has published a paper on Ti02 Wannier 
functions. It would be interesting to compare your results to his.

Our consensus was that the localization functional can display
minima that are not meaningful - usually marked by the fact that the
MLWFs do not look localized, or symmetric, and especially that they are
not real-valued, but are complex-valued. These incorrect minima are 
somewhat connected to the fact that there are few points in the BZ where 
a smooth continuous choice of phase factors was not achieved.

There are cases when more than one good minimum can exist - the first
one that comes to my mind is benzene, where you can have two equivalent
choices for the location of the three double bonds on the aromatic ring.

It could be that yours is another case - there is more that one
meanigful minimum - and, the notion of "meaningful minimum" is rather
heuristic.

Let us know what you find,

			nicola




lan haiping wrote:
> 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
> 
> 
> ------------------------------------------------------------------------
> 
>  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
> 
> 
> ------------------------------------------------------------------------
> 
>  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


-- 
---------------------------------------------------------------------
Prof Nicola Marzari   Department of Materials Science and Engineering
13-5066   MIT   77 Massachusetts Avenue   Cambridge MA 02139-4307 USA
tel 617.4522758 fax 2586534 marzari@mit.edu http://quasiamore.mit.edu

From lanhaiping@gmail.com  Tue Dec 19 02:54:14 2006
From: lanhaiping@gmail.com (lan haiping)
Date: Tue, 19 Dec 2006 10:54:14 +0800
Subject: [Wannier] Question about final spreads
In-Reply-To: <458602DF.4050502@mit.edu>
References: <c92002fa0612171652t22c3d215t59410b2d6126332e@mail.gmail.com>
 <458602DF.4050502@mit.edu>
Message-ID: <c92002fa0612181854l7675dcfdoef20976fb4060fe3@mail.gmail.com>

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Dear Nicola,

 Thank you.
I do want to repeat Prof  Postermak's works on tio2.
Last night, i also tried to change projection functions for  rutile tio2.
Indeed, i also found there
are 2 more minimum spreads founded with different stating projection
functions.

For rutile case, when i started with s/px/py/pz on O sites, i obtained total
spreads  of 14.919.  while changing projection functions to sp2/pz on O
sites,  i obtained total spreads of 14.4672.  But wannier function centers
can both be classified into 4 groups.

Regards,

Hai-Ping



On 12/18/06, Nicola Marzari <marzari@mit.edu> wrote:
>
>
>
> Dear Hai-Ping,
>
>
> I believe Michel Posternak has published a paper on Ti02 Wannier
> functions. It would be interesting to compare your results to his.
>
> Our consensus was that the localization functional can display
> minima that are not meaningful - usually marked by the fact that the
> MLWFs do not look localized, or symmetric, and especially that they are
> not real-valued, but are complex-valued. These incorrect minima are
> somewhat connected to the fact that there are few points in the BZ where
> a smooth continuous choice of phase factors was not achieved.
>
> There are cases when more than one good minimum can exist - the first
> one that comes to my mind is benzene, where you can have two equivalent
> choices for the location of the three double bonds on the aromatic ring.
>
> It could be that yours is another case - there is more that one
> meanigful minimum - and, the notion of "meaningful minimum" is rather
> heuristic.
>
> Let us know what you find,
>
>                        nicola
>
>
>
>
> lan haiping wrote:
> > 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
> >
> >
> > ------------------------------------------------------------------------
>
> >
> >  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
> >
> >
> > ------------------------------------------------------------------------
>
> >
> >  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
>
>
> --
> ---------------------------------------------------------------------
> Prof Nicola Marzari   Department of Materials Science and Engineering
> 13-5066   MIT   77 Massachusetts Avenue   Cambridge MA 02139-4307 USA
> tel 617.4522758 fax 2586534 marzari@mit.edu http://quasiamore.mit.edu
> _______________________________________________
> Wannier mailing list
> Wannier@quantum-espresso.org
> http://www.democritos.it/mailman/listinfo/wannier
>



-- 
Hai-Ping Lan
Department of Electronics ,
Peking University , Bejing, 100871

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<div>Dear Nicola,</div>
<div>&nbsp;</div>
<div>&nbsp;Thank you.</div>
<div>I do want&nbsp;to&nbsp;repeat Prof &nbsp;Postermak's works on tio2.</div>
<div>Last night, i also tried to&nbsp;change projection functions for&nbsp; rutile tio2. Indeed, i also found there&nbsp;</div>
<div>are 2 more minimum spreads founded with different stating projection functions.</div>
<div>&nbsp;</div>
<div>For&nbsp;rutile case, when i started with s/px/py/pz on O sites, i obtained total spreads&nbsp;&nbsp;of 14.919.&nbsp; while&nbsp;changing projection functions&nbsp;to sp2/pz on O sites,&nbsp;&nbsp;i obtained total spreads of 14.4672.&nbsp; But&nbsp;wannier&nbsp;function&nbsp;centers can both&nbsp;be classified into 4 groups.
</div>
<div>&nbsp;</div>
<div>Regards,</div>
<div>&nbsp;</div>
<div>Hai-Ping</div>
<div>&nbsp;</div>
<div><br>&nbsp;</div>
<div><span class="gmail_quote">On 12/18/06, <b class="gmail_sendername">Nicola Marzari</b> &lt;<a onclick="return top.js.OpenExtLink(window,event,this)" href="mailto:marzari@mit.edu" target="_blank">marzari@mit.edu</a>&gt; wrote:
</span> 
<blockquote class="gmail_quote" style="PADDING-LEFT: 1ex; MARGIN: 0px 0px 0px 0.8ex; BORDER-LEFT: #ccc 1px solid"><br><br>Dear Hai-Ping,<br><br><br>I believe Michel Posternak has published a paper on Ti02 Wannier<br>functions. It would be interesting to compare your results to his. 
<br><br>Our consensus was that the localization functional can display<br>minima that are not meaningful - usually marked by the fact that the<br>MLWFs do not look localized, or symmetric, and especially that they are<br>
not real-valued, but are complex-valued. These incorrect minima are<br>somewhat connected to the fact that there are few points in the BZ where<br>a smooth continuous choice of phase factors was not achieved.<br><br>There are cases when more than one good minimum can exist - the first 
<br>one that comes to my mind is benzene, where you can have two equivalent<br>choices for the location of the three double bonds on the aromatic ring.<br><br>It could be that yours is another case - there is more that one 
<br>meanigful minimum - and, the notion of &quot;meaningful minimum&quot; is rather<br>heuristic.<br><br>Let us know what you find,<br><br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; nicola<br><br><br><br><br>lan haiping wrote:<br>&gt; Dear All, 
<br>&gt;<br>&gt; I came to confusion about final results of wannierise procedure.<br>&gt;&nbsp;&nbsp;I am trying to analyse anatase tio2 wannier function and&nbsp;&nbsp;born charge<br>&gt; with wannier90.x.<br>&gt; I performed 2 calculations with 2 different projection functions sets, 
<br>&gt; other settings are same. Both reached convergenc (error deltas for total<br>&gt; Omega are about 1E-10). But the total spreads and wannier centers are<br>&gt; quite different.<br>&gt; For my first calculation, i just start with sp2 and pz&nbsp;&nbsp;functions at O 
<br>&gt; sites, the total spreads finally obtained is 14.397.<br>&gt; While for the second calculation, the projetion functions are s/px/py/pz<br>&gt; functions at O sites,&nbsp;&nbsp;the total spreads finally obtained is then<br>&gt; 
15.2170.<br>&gt;<br>&gt; The wannier functions of second calculation could be classed into 4<br>&gt; groups by spreads , while the conclusion is not hold for the fist<br>&gt; calculation ( the wannier functions are then classed into 8 groups ). 
<br>&gt;<br>&gt; According to MV paper, the MLWFs reflect structures'&nbsp;&nbsp;symmetry by<br>&gt; spreads. So, Both 2 calculations are not correct.<br>&gt;<br>&gt; Would you please give me some comments ?<br>&gt; And input files are below : 
<br>&gt;<br>&gt; *num_wann = 16<br>&gt; num_iter = 2000<br>&gt; guiding_centres = T<br>&gt; exclude_bands = 1 2 3 4 5 6 7 8 25 26 27 28 29 30<br>&gt; begin projections<br>&gt; O : sp2<br>&gt; O : pz<br>&gt; end projections 
<br>&gt; begin atoms_cart<br>&gt; Ti&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 0.000000000&nbsp;&nbsp; -0.000000000&nbsp;&nbsp; 0.000000000<br>&gt; Ti&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 0.000000000&nbsp;&nbsp; 1.892500000&nbsp;&nbsp; 2.378500000<br>&gt; O&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;0.000000000&nbsp;&nbsp; 0.000000000&nbsp;&nbsp; 1.979863400<br>&gt; O&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;0.000000000
 &nbsp;&nbsp;-0.000000000&nbsp;&nbsp; 7.534136600<br>&gt; O&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;0.000000000&nbsp;&nbsp; 1.892500000&nbsp;&nbsp;&nbsp;&nbsp;4.358363400<br>&gt; O&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;0.000000000&nbsp;&nbsp; 1.892500000&nbsp;&nbsp; 0.398636600<br>&gt; end atoms_cart*<br>&gt;<br>&gt; *begin unit_cell_cart<br>&gt; Ang<br>
&gt;&nbsp;&nbsp;&nbsp;&nbsp;1.8925&nbsp;&nbsp;-1.8925&nbsp;&nbsp;4.757<br>&gt;&nbsp;&nbsp;&nbsp;&nbsp;1.8925&nbsp;&nbsp; 1.8925&nbsp;&nbsp;4.757<br>&gt;&nbsp;&nbsp; -1.8925&nbsp;&nbsp;-1.8925&nbsp;&nbsp;4.757<br>&gt; end unit_cell_cart<br>&gt; mp_grid :&nbsp;&nbsp;6 6 6<br>&gt; begin kpoints<br>&gt; ......<br>&gt; end kpoints*<br>&gt;<br>&gt; two final spreads and wannier centers are attached. 
<br>&gt;<br>&gt; *Regards*<br>&gt;<br>&gt; Hai-Ping<br>&gt;<br>&gt;<br>&gt;<br>&gt; --<br>&gt; Hai-Ping Lan<br>&gt; Department of Electronics ,<br>&gt; Peking University , Bejing, 100871<br>&gt;<br>&gt;<br>&gt; ------------------------------------------------------------------------ 
<br>&gt;<br>&gt;&nbsp;&nbsp;Final State<br>&gt;&nbsp;&nbsp;WF centre and spread&nbsp;&nbsp;&nbsp;&nbsp;1&nbsp;&nbsp;( -0.057359,&nbsp;&nbsp;0.368438,&nbsp;&nbsp;2.144012 )&nbsp;&nbsp;&nbsp;&nbsp; 0.81913203<br>&gt;&nbsp;&nbsp;WF centre and spread&nbsp;&nbsp;&nbsp;&nbsp;2&nbsp;&nbsp;( -0.057359, -0.368438,&nbsp;&nbsp;2.144012 )&nbsp;&nbsp;&nbsp;&nbsp; 0.81913201<br>&gt;&nbsp;&nbsp;WF centre and spread&nbsp;&nbsp;&nbsp;&nbsp;3&nbsp;&nbsp;(&nbsp;&nbsp; 
0.207447,&nbsp;&nbsp;0.000000,&nbsp;&nbsp;1.889906 )&nbsp;&nbsp;&nbsp;&nbsp; 1.06292459<br>&gt;&nbsp;&nbsp;WF centre and spread&nbsp;&nbsp;&nbsp;&nbsp;4&nbsp;&nbsp;( -0.197679,&nbsp;&nbsp;0.225730,&nbsp;&nbsp;7.480939 )&nbsp;&nbsp;&nbsp;&nbsp; 0.95045581<br>&gt;&nbsp;&nbsp;WF centre and spread&nbsp;&nbsp;&nbsp;&nbsp;5&nbsp;&nbsp;( -0.197683, -0.225729,&nbsp;&nbsp;7.480937 )&nbsp;&nbsp;&nbsp;&nbsp; 0.95045348
 <br>&gt;&nbsp;&nbsp;WF centre and spread&nbsp;&nbsp;&nbsp;&nbsp;6&nbsp;&nbsp;(&nbsp;&nbsp;0.383935,&nbsp;&nbsp;0.000000,&nbsp;&nbsp;7.384053 )&nbsp;&nbsp;&nbsp;&nbsp; 0.82485652<br>&gt;&nbsp;&nbsp;WF centre and spread&nbsp;&nbsp;&nbsp;&nbsp;7&nbsp;&nbsp;( -0.197693,&nbsp;&nbsp;2.118226,&nbsp;&nbsp;4.411569 )&nbsp;&nbsp;&nbsp;&nbsp; 0.95044526<br>&gt;&nbsp;&nbsp;WF centre and spread&nbsp;&nbsp;&nbsp;&nbsp;8&nbsp;&nbsp;( -0.197669
 ,&nbsp;&nbsp;1.666767,&nbsp;&nbsp;4.411555 )&nbsp;&nbsp;&nbsp;&nbsp; 0.95046140<br>&gt;&nbsp;&nbsp;WF centre and spread&nbsp;&nbsp;&nbsp;&nbsp;9&nbsp;&nbsp;(&nbsp;&nbsp;0.383935,&nbsp;&nbsp;1.892503,&nbsp;&nbsp;4.508447 )&nbsp;&nbsp;&nbsp;&nbsp; 0.82485530<br>&gt;&nbsp;&nbsp;WF centre and spread&nbsp;&nbsp; 10&nbsp;&nbsp;( -0.057359,&nbsp;&nbsp;2.260938,&nbsp;&nbsp;0.234488 )&nbsp;&nbsp;&nbsp;&nbsp; 0.81913205<br>&gt;&nbsp;&nbsp;WF centre and spread&nbsp;&nbsp; 11&nbsp;&nbsp;( - 
0.057359,&nbsp;&nbsp;1.524062,&nbsp;&nbsp;0.234488 )&nbsp;&nbsp;&nbsp;&nbsp; 0.81913192<br>&gt;&nbsp;&nbsp;WF centre and spread&nbsp;&nbsp; 12&nbsp;&nbsp;(&nbsp;&nbsp;0.207447,&nbsp;&nbsp;1.892500,&nbsp;&nbsp;0.488594 )&nbsp;&nbsp;&nbsp;&nbsp; 1.06292460<br>&gt;&nbsp;&nbsp;WF centre and spread&nbsp;&nbsp; 13&nbsp;&nbsp;( -0.090800,&nbsp;&nbsp;0.000000,&nbsp;&nbsp;1.575406 )&nbsp;&nbsp;&nbsp;&nbsp; 0.88848488
 <br>&gt;&nbsp;&nbsp;WF centre and spread&nbsp;&nbsp; 14&nbsp;&nbsp;(&nbsp;&nbsp;0.012349,&nbsp;&nbsp;0.000000,&nbsp;&nbsp;7.957177 )&nbsp;&nbsp;&nbsp;&nbsp; 0.88317336<br>&gt;&nbsp;&nbsp;WF centre and spread&nbsp;&nbsp; 15&nbsp;&nbsp;(&nbsp;&nbsp;0.012349,&nbsp;&nbsp;1.892503,&nbsp;&nbsp;3.935322 )&nbsp;&nbsp;&nbsp;&nbsp; 0.88317159<br>&gt;&nbsp;&nbsp;WF centre and spread&nbsp;&nbsp; 16&nbsp;&nbsp;( -0.090800
 ,&nbsp;&nbsp;1.892500,&nbsp;&nbsp;0.803094 )&nbsp;&nbsp;&nbsp;&nbsp; 0.88848495<br>&gt;&nbsp;&nbsp;Sum of centres and spreads (&nbsp;&nbsp;0.005703, 15.139999, 57.083998 )&nbsp;&nbsp;&nbsp;&nbsp;14.39721976<br>&gt;<br>&gt;<br>&gt; ------------------------------------------------------------------------ 
<br>&gt;<br>&gt;&nbsp;&nbsp;Final State<br>&gt;&nbsp;&nbsp; WF centre and spread&nbsp;&nbsp;&nbsp;&nbsp;1&nbsp;&nbsp;(&nbsp;&nbsp;0.000000,&nbsp;&nbsp;0.000000,&nbsp;&nbsp;1.913455 )&nbsp;&nbsp;&nbsp;&nbsp; 1.16247952<br>&gt;&nbsp;&nbsp; WF centre and spread&nbsp;&nbsp;&nbsp;&nbsp;2&nbsp;&nbsp;(&nbsp;&nbsp;0.000000,&nbsp;&nbsp;0.000000,&nbsp;&nbsp;7.509543 )&nbsp;&nbsp;&nbsp;&nbsp; 1.20049037<br>&gt;&nbsp;&nbsp; WF centre and spread&nbsp;&nbsp;&nbsp;&nbsp;3&nbsp;&nbsp;(&nbsp;&nbsp; 
0.000000,&nbsp;&nbsp;1.892500,&nbsp;&nbsp;4.382956 )&nbsp;&nbsp;&nbsp;&nbsp; 1.20048903<br>&gt;&nbsp;&nbsp; WF centre and spread&nbsp;&nbsp;&nbsp;&nbsp;4&nbsp;&nbsp;(&nbsp;&nbsp;0.000000,&nbsp;&nbsp;1.892500,&nbsp;&nbsp;0.465045 )&nbsp;&nbsp;&nbsp;&nbsp; 1.16247952<br>&gt;&nbsp;&nbsp; WF centre and spread&nbsp;&nbsp;&nbsp;&nbsp;5&nbsp;&nbsp;(&nbsp;&nbsp;0.000000,&nbsp;&nbsp;0.000000,&nbsp;&nbsp;2.004457 )&nbsp;&nbsp;&nbsp;&nbsp; 1.20048828
 <br>&gt;&nbsp;&nbsp; WF centre and spread&nbsp;&nbsp;&nbsp;&nbsp;6&nbsp;&nbsp;(&nbsp;&nbsp;0.000000,&nbsp;&nbsp;0.000000,&nbsp;&nbsp;7.600545 )&nbsp;&nbsp;&nbsp;&nbsp; 1.16248168<br>&gt;&nbsp;&nbsp; WF centre and spread&nbsp;&nbsp;&nbsp;&nbsp;7&nbsp;&nbsp;(&nbsp;&nbsp;0.000000,&nbsp;&nbsp;1.892500,&nbsp;&nbsp;4.291955 )&nbsp;&nbsp;&nbsp;&nbsp; 1.16248025<br>&gt;&nbsp;&nbsp; WF centre and spread&nbsp;&nbsp;&nbsp;&nbsp;8&nbsp;&nbsp;(&nbsp;&nbsp;0.000000
 ,&nbsp;&nbsp;1.892497,&nbsp;&nbsp;0.374043 )&nbsp;&nbsp;&nbsp;&nbsp; 1.20048827<br>&gt;&nbsp;&nbsp; WF centre and spread&nbsp;&nbsp;&nbsp;&nbsp;9&nbsp;&nbsp;(&nbsp;&nbsp;0.000000,&nbsp;&nbsp;0.000000,&nbsp;&nbsp;1.522196 )&nbsp;&nbsp;&nbsp;&nbsp; 0.75151445<br>&gt;&nbsp;&nbsp; WF centre and spread&nbsp;&nbsp; 10&nbsp;&nbsp;(&nbsp;&nbsp;0.000000,&nbsp;&nbsp;0.000000,&nbsp;&nbsp;7.991803 )&nbsp;&nbsp;&nbsp;&nbsp; 0.75151691<br>&gt;&nbsp;&nbsp; WF centre and spread&nbsp;&nbsp; 11&nbsp;&nbsp;(&nbsp;&nbsp; 
0.000000,&nbsp;&nbsp;1.892500,&nbsp;&nbsp;3.900696 )&nbsp;&nbsp;&nbsp;&nbsp; 0.75151511<br>&gt;&nbsp;&nbsp; WF centre and spread&nbsp;&nbsp; 12&nbsp;&nbsp;(&nbsp;&nbsp;0.000000,&nbsp;&nbsp;1.892501,&nbsp;&nbsp;0.856304 )&nbsp;&nbsp;&nbsp;&nbsp; 0.75151453<br>&gt;&nbsp;&nbsp; WF centre and spread&nbsp;&nbsp; 13&nbsp;&nbsp;(&nbsp;&nbsp;0.000000,&nbsp;&nbsp;0.000000,&nbsp;&nbsp;2.312422 )&nbsp;&nbsp;&nbsp;&nbsp; 0.68819033
 <br>&gt;&nbsp;&nbsp; WF centre and spread&nbsp;&nbsp; 14&nbsp;&nbsp;(&nbsp;&nbsp;0.000000,&nbsp;&nbsp;0.000000,&nbsp;&nbsp;7.201578 )&nbsp;&nbsp;&nbsp;&nbsp; 0.68819219<br>&gt;&nbsp;&nbsp; WF centre and spread&nbsp;&nbsp; 15&nbsp;&nbsp;(&nbsp;&nbsp;0.000000,&nbsp;&nbsp;1.892500,&nbsp;&nbsp;4.690922 )&nbsp;&nbsp;&nbsp;&nbsp; 0.68819114<br>&gt;&nbsp;&nbsp; WF centre and spread&nbsp;&nbsp; 16&nbsp;&nbsp;(&nbsp;&nbsp;0.000000
 ,&nbsp;&nbsp;1.892502,&nbsp;&nbsp;0.066078 )&nbsp;&nbsp;&nbsp;&nbsp; 0.68819026<br>&gt;&nbsp;&nbsp; Sum of centres and spreads (&nbsp;&nbsp;0.000000, 15.139999, 57.083998 )&nbsp;&nbsp;&nbsp;&nbsp;15.21070184<br><br><br>--<br>---------------------------------------------------------------------<br>Prof Nicola Marzari&nbsp;&nbsp; Department of Materials Science and Engineering 
<br>13-5066&nbsp;&nbsp; MIT&nbsp;&nbsp; 77 Massachusetts Avenue&nbsp;&nbsp; Cambridge MA 02139-4307 USA<br>tel 617.4522758 fax 2586534 <a onclick="return top.js.OpenExtLink(window,event,this)" href="mailto:marzari@mit.edu" target="_blank">marzari@mit.edu
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http://www.democritos.it/mailman/listinfo/wannier</a><br></blockquote></div><br><br clear="all"><br>-- <br>Hai-Ping Lan <br>Department of Electronics ,<br>Peking University , Bejing, 100871 

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From marzari@MIT.EDU  Tue Dec 19 03:48:43 2006
From: marzari@MIT.EDU (Nicola Marzari)
Date: Mon, 18 Dec 2006 22:48:43 -0500
Subject: [Wannier] Question about final spreads
In-Reply-To: <c92002fa0612181854l7675dcfdoef20976fb4060fe3@mail.gmail.com>
References: <c92002fa0612171652t22c3d215t59410b2d6126332e@mail.gmail.com>	 <458602DF.4050502@mit.edu> <c92002fa0612181854l7675dcfdoef20976fb4060fe3@mail.gmail.com>
Message-ID: <4587611B.3040207@mit.edu>


Thanks - I also remember that in our work on MnO we needed really
very very accurate minimizations to get to the true minimum - it's
described a bit in the 2002 PRB with Posternak (we needed 10000-50000
steps, albeit the algorithm now is much better).

So I wonder if, by continuing the minimization for many more iterations,
you would actually converge to a unique minimum.

			nicola


lan haiping wrote:
> Dear Nicola,
>  
>  Thank you.
> I do want to repeat Prof  Postermak's works on tio2.
> Last night, i also tried to change projection functions for  rutile 
> tio2. Indeed, i also found there 
> are 2 more minimum spreads founded with different stating projection 
> functions.
>  
> For rutile case, when i started with s/px/py/pz on O sites, i obtained 
> total spreads  of 14.919.  while changing projection functions to sp2/pz 
> on O sites,  i obtained total spreads of 14.4672.  
> But wannier function centers can both be classified into 4 groups.
>  
> Regards,
>  
> Hai-Ping


-- 
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Prof Nicola Marzari   Department of Materials Science and Engineering
13-5066   MIT   77 Massachusetts Avenue   Cambridge MA 02139-4307 USA
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