From sd.wang000 at 163.com  Mon Apr  5 16:56:04 2010
From: sd.wang000 at 163.com (sd.wang000)
Date: Mon, 5 Apr 2010 22:56:04 +0800 (CST)
Subject: [Wannier] wannier center
Message-ID: <bc9ab6.59fa.127ce78a06b.Coremail.sd.wang000@163.com>

Dear all:
I use the midpoint.x code to get wannier centers, the output file is;
 ======================================================================
              =                                            =
              =     *** WanT *** Wannier Transport Code    =
              =        (www.wannier-transport.org)         =
              =      Ultra Soft Pseudopotential Implem.    =
              =                                            =
  ======================================================================

  Program <midpoint>  v. 2.1.0  starts ...
  Date  5Apr2010 at 20:49:32 
     Serial run.
          BUILT :    Thu Apr  1 20:30:37 2010
           HOST :    x86_64-unknown-linux-gnu
           ARCH :    amd64
             CC :    icc
            CPP :    cpp
            F90 :    mpif90
            F77 :    ifort
         DFLAGS :    -D__INTEL -D__FFTW -D__USE_INTERNAL_FFTW -D__MPI -D__PARA
      BLAS LIBS :    -L/usr/local/intel/cmkl/8.0/lib/em64t -lmkl_em64t -lguide -lpthread
    LAPACK LIBS :    -lmkl_lapack
       FFT LIBS :    
      MASS LIBS :    

  DFT-data fmt automaticaly detected: qexml
  DFT-data read from file: 33.save/data-file.xml

  ======================================================================
  =  DFT data                                                          =
  ======================================================================
 <LATTICE>
  Alat  =      38.8071800 (Bohr)
  Alat  =      20.5358671 (Ang )
  Omega =   68086.6835331 (Bohr^3)
  Omega =   10089.3934911 (Ang^3 )
  Crystal axes:
                in units of Bohr                 in Alat units
    a(1) = ( 38.8072  0.0000  0.0000 )     (   1.0000  0.0000  0.0000 )
    a(2) = (  0.0000 45.2104  0.0000 )     (   0.0000  1.1650  0.0000 )
    a(3) = (  0.0000  0.0000 38.8072 )     (   0.0000  0.0000  1.0000 )
  Crystal axes: (Ang)
    a(1) = ( 20.5359  0.0000  0.0000 )
    a(2) = (  0.0000 23.9243  0.0000 )
    a(3) = (  0.0000  0.0000 20.5359 )
   Reciprocal lattice vectors:
                in units of Bohr^-1              in 2Pi/Alat units
    b(1) = (  0.1619  0.0000  0.0000 )     (   1.0000  0.0000  0.0000 )
    b(2) = (  0.0000  0.1390  0.0000 )     (   0.0000  0.8584  0.0000 )
    b(3) = (  0.0000  0.0000  0.1619 )     (   0.0000  0.0000  1.0000 )
 </LATTICE>
 <IONS>
  Number of chemical species =  3
  Atomic positions: (cart. coord. in Bohr)
     Au   tau(   1 ) = (   0.0000000   3.9568111   3.9567801 )
     Au   tau(   2 ) = (   3.9567801   3.9568111   0.0000000 )
     Au   tau(   3 ) = (   7.9135601   3.9568111   3.9567801 )
     Au   tau(   4 ) = (   3.9567801   7.9131701   3.9567801 )
     Au   tau(   5 ) = (   0.0000000   0.0000000   7.9135601 )
     Au   tau(   6 ) = (   0.0000000   3.9568111  11.8699521 )
     Au   tau(   7 ) = (   3.9567801   0.0000000  11.8699521 )
     Au   tau(   8 ) = (   3.9567801   3.9568111   7.9135601 )
     Au   tau(   9 ) = (   7.9135601   0.0000000   7.9135601 )
     Au   tau(  10 ) = (   7.9135601   3.9568111  11.8699521 )
     Au   tau(  11 ) = (  11.8699521   3.9568111   7.9135601 )
     Au   tau(  12 ) = (   0.0000000   7.9131701   7.9135601 )
     Au   tau(  13 ) = (   3.9567801   7.9131701  11.8699521 )
     Au   tau(  14 ) = (   3.9567801  11.8699813   7.9135601 )
     Au   tau(  15 ) = (   0.0000000  37.1045984   3.9567801 )
     Au   tau(  16 ) = (   3.9567801  33.1482394   3.9567801 )
     Au   tau(  17 ) = (   3.9567801  37.1045984   0.0000000 )
     Au   tau(  18 ) = (   7.9135601  37.1045984   3.9567801 )
     Au   tau(  19 ) = (   3.9567801  29.1914283   7.9135601 )
     Au   tau(  20 ) = (   0.0000000  37.1045984  11.8699521 )
     Au   tau(  21 ) = (   3.9567801  33.1482394  11.8699521 )
     Au   tau(  22 ) = (   3.9567801  37.1045984   7.9131721 )
     Au   tau(  23 ) = (   7.9135601  33.1482394   7.9131721 )
     Au   tau(  24 ) = (   7.9135601  37.1045984  11.8699521 )
     Au   tau(  25 ) = (  11.8699521  37.1045984   7.9131721 )
     Au   tau(  26 ) = (   3.9567801  41.1201830   3.9567801 )
     Au   tau(  27 ) = (   0.0000000  41.1201830   7.9135601 )
     Au   tau(  28 ) = (   7.9135601  41.1201830   7.9135601 )
     N    tau(  29 ) = (   4.0576787  25.4041560   7.8988134 )
     N    tau(  30 ) = (   4.0576787  15.6558972   7.8988134 )
     C    tau(  31 ) = (   4.0576787  23.0758222   7.8988134 )
     C    tau(  32 ) = (   4.0576787  20.5300266   7.8988134 )
     C    tau(  33 ) = (   4.0576787  17.9842310   7.8988134 )
 </IONS>

  ======================================================================
  =  Computing mid points of bonds                                     =
  ======================================================================
        Output fmt :   crystal
    Bond len. toll :      0.1000
     Cutoff radius :      5.0000 [Ang]

  # Valid bond types:     5
  Minimum bond length [Ang]:
    Au -- Au   :  2.164430
    Au -- N    :  2.004146
    Au -- C    :  3.235970
    N  -- C    :  1.232101
    C  -- C    :  1.347176

  ======================================================================
  Atomic positions [crystal]:
   33
  Au       0.000000000    0.087520000    0.101960000
  Au       0.101960000    0.087520000    0.000000000
  Au       0.203920000    0.087520000    0.101960000
  Au       0.101960000    0.175030000    0.101960000
  Au       0.000000000    0.000000000    0.203920000
  Au       0.000000000    0.087520000    0.305870000
  Au       0.101960000    0.000000000    0.305870000
  Au       0.101960000    0.087520000    0.203920000
  Au       0.203920000    0.000000000    0.203920000
  Au       0.203920000    0.087520000    0.305870000
  Au       0.305870000    0.087520000    0.203920000
  Au       0.000000000    0.175030000    0.203920000
  Au       0.101960000    0.175030000    0.305870000
  Au       0.101960000    0.262550000    0.203920000
  Au       0.000000000    0.820710000    0.101960000
  Au       0.101960000    0.733200000    0.101960000
  Au       0.101960000    0.820710000    0.000000000
  Au       0.203920000    0.820710000    0.101960000
  Au       0.101960000    0.645680000    0.203920000
  Au       0.000000000    0.820710000    0.305870000
  Au       0.101960000    0.733200000    0.305870000
  Au       0.101960000    0.820710000    0.203910000
  Au       0.203920000    0.733200000    0.203910000
  Au       0.203920000    0.820710000    0.305870000
  Au       0.305870000    0.820710000    0.203910000
  Au       0.101960000    0.909530000    0.101960000
  Au       0.000000000    0.909530000    0.203920000
  Au       0.203920000    0.909530000    0.203920000
  N        0.104560000    0.561910000    0.203540000
  N        0.104560000    0.346290000    0.203540000
  C        0.104560000    0.510410000    0.203540000
  C        0.104560000    0.454100000    0.203540000
  C        0.104560000    0.397790000    0.203540000
  ======================================================================
  Bond mid points [crystal]:
   10
  H        0.104560000    0.425945000    0.203540000   C  -- C  
  H        0.104560000    0.482255000    0.203540000   C  -- C  
  H        0.104560000    0.372040000    0.203540000   N  -- C  
  H        0.104560000    0.536160000    0.203540000   N  -- C  
  H        0.103260000    0.578045000    0.203730000   Au -- C  
  H        0.103260000    0.603795000    0.203730000   Au -- N  
  H        0.103260000    0.330170000    0.203730000   Au -- C  
  H        0.103260000    0.304420000    0.203730000   Au -- N  
  H        0.203920000   -0.045235000    0.203920000   Au -- Au 
  H        0.000000000   -0.045235000    0.203920000   Au -- Au 

  ======================================================================
   <global routines>
             clock number :     3
                 midpoint :     0.00s CPU 
 
             want_dftread :     0.13s CPU
                want_init :  
 
How can I get my wannier centers? 
 
 
S.D.Wang
Southeast University in Najing ,China
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From sd.wang000 at gmail.com  Tue Apr  6 06:51:07 2010
From: sd.wang000 at gmail.com (shudong wang)
Date: Tue, 6 Apr 2010 12:51:07 +0800
Subject: [Wannier] wannier center
Message-ID: <l2xf82f94a11004052151td74dbbd6j84e6ee9932ad9e9@mail.gmail.com>

Dear all:
I use the midpoint.x code to get wannier centers, the output file is;
 ======================================================================
              =                                            =
              =     *** WanT *** Wannier Transport Code    =
              =        (www.wannier-transport.org)         =
              =      Ultra Soft Pseudopotential Implem.    =
              =                                            =
  ======================================================================

  Program <midpoint>  v. 2.1.0  starts ...
  Date  5Apr2010 at 20:49:32
     Serial run.
          BUILT :    Thu Apr  1 20:30:37 2010
           HOST :    x86_64-unknown-linux-gnu
           ARCH :    amd64
             CC :    icc
            CPP :    cpp
            F90 :    mpif90
            F77 :    ifort
         DFLAGS :    -D__INTEL -D__FFTW -D__USE_INTERNAL_FFTW -D__MPI
-D__PARA
      BLAS LIBS :    -L/usr/local/intel/cmkl/8.0/lib/em64t -lmkl_em64t
-lguide -lpthread
    LAPACK LIBS :    -lmkl_lapack
       FFT LIBS :
      MASS LIBS :

  DFT-data fmt automaticaly detected: qexml
  DFT-data read from file: 33.save/data-file.xml

  ======================================================================
  =  DFT data                                                          =
  ======================================================================
 <LATTICE>
  Alat  =      38.8071800 (Bohr)
  Alat  =      20.5358671 (Ang )
  Omega =   68086.6835331 (Bohr^3)
  Omega =   10089.3934911 (Ang^3 )
  Crystal axes:
                in units of Bohr                 in Alat units
    a(1) = ( 38.8072  0.0000  0.0000 )     (   1.0000  0.0000  0.0000 )
    a(2) = (  0.0000 45.2104  0.0000 )     (   0.0000  1.1650  0.0000 )
    a(3) = (  0.0000  0.0000 38.8072 )     (   0.0000  0.0000  1.0000 )
  Crystal axes: (Ang)
    a(1) = ( 20.5359  0.0000  0.0000 )
    a(2) = (  0.0000 23.9243  0.0000 )
    a(3) = (  0.0000  0.0000 20.5359 )
   Reciprocal lattice vectors:
                in units of Bohr^-1              in 2Pi/Alat units
    b(1) = (  0.1619  0.0000  0.0000 )     (   1.0000  0.0000  0.0000 )
    b(2) = (  0.0000  0.1390  0.0000 )     (   0.0000  0.8584  0.0000 )
    b(3) = (  0.0000  0.0000  0.1619 )     (   0.0000  0.0000  1.0000 )
 </LATTICE>
 <IONS>
  Number of chemical species =  3
  Atomic positions: (cart. coord. in Bohr)
     Au   tau(   1 ) = (   0.0000000   3.9568111   3.9567801 )
     Au   tau(   2 ) = (   3.9567801   3.9568111   0.0000000 )
     Au   tau(   3 ) = (   7.9135601   3.9568111   3.9567801 )
     Au   tau(   4 ) = (   3.9567801   7.9131701   3.9567801 )
     Au   tau(   5 ) = (   0.0000000   0.0000000   7.9135601 )
     Au   tau(   6 ) = (   0.0000000   3.9568111  11.8699521 )
     Au   tau(   7 ) = (   3.9567801   0.0000000  11.8699521 )
     Au   tau(   8 ) = (   3.9567801   3.9568111   7.9135601 )
     Au   tau(   9 ) = (   7.9135601   0.0000000   7.9135601 )
     Au   tau(  10 ) = (   7.9135601   3.9568111  11.8699521 )
     Au   tau(  11 ) = (  11.8699521   3.9568111   7.9135601 )
     Au   tau(  12 ) = (   0.0000000   7.9131701   7.9135601 )
     Au   tau(  13 ) = (   3.9567801   7.9131701  11.8699521 )
     Au   tau(  14 ) = (   3.9567801  11.8699813   7.9135601 )
     Au   tau(  15 ) = (   0.0000000  37.1045984   3.9567801 )
     Au   tau(  16 ) = (   3.9567801  33.1482394   3.9567801 )
     Au   tau(  17 ) = (   3.9567801  37.1045984   0.0000000 )
     Au   tau(  18 ) = (   7.9135601  37.1045984   3.9567801 )
     Au   tau(  19 ) = (   3.9567801  29.1914283   7.9135601 )
     Au   tau(  20 ) = (   0.0000000  37.1045984  11.8699521 )
     Au   tau(  21 ) = (   3.9567801  33.1482394  11.8699521 )
     Au   tau(  22 ) = (   3.9567801  37.1045984   7.9131721 )
     Au   tau(  23 ) = (   7.9135601  33.1482394   7.9131721 )
     Au   tau(  24 ) = (   7.9135601  37.1045984  11.8699521 )
     Au   tau(  25 ) = (  11.8699521  37.1045984   7.9131721 )
     Au   tau(  26 ) = (   3.9567801  41.1201830   3.9567801 )
     Au   tau(  27 ) = (   0.0000000  41.1201830   7.9135601 )
     Au   tau(  28 ) = (   7.9135601  41.1201830   7.9135601 )
     N    tau(  29 ) = (   4.0576787  25.4041560   7.8988134 )
     N    tau(  30 ) = (   4.0576787  15.6558972   7.8988134 )
     C    tau(  31 ) = (   4.0576787  23.0758222   7.8988134 )
     C    tau(  32 ) = (   4.0576787  20.5300266   7.8988134 )
     C    tau(  33 ) = (   4.0576787  17.9842310   7.8988134 )
 </IONS>

  ======================================================================
  =  Computing mid points of bonds                                     =
  ======================================================================
        Output fmt :   crystal
    Bond len. toll :      0.1000
     Cutoff radius :      5.0000 [Ang]

  # Valid bond types:     5
  Minimum bond length [Ang]:
    Au -- Au   :  2.164430
    Au -- N    :  2.004146
    Au -- C    :  3.235970
    N  -- C    :  1.232101
    C  -- C    :  1.347176

  ======================================================================
  Atomic positions [crystal]:
   33
  Au       0.000000000    0.087520000    0.101960000
  Au       0.101960000    0.087520000    0.000000000
  Au       0.203920000    0.087520000    0.101960000
  Au       0.101960000    0.175030000    0.101960000
  Au       0.000000000    0.000000000    0.203920000
  Au       0.000000000    0.087520000    0.305870000
  Au       0.101960000    0.000000000    0.305870000
  Au       0.101960000    0.087520000    0.203920000
  Au       0.203920000    0.000000000    0.203920000
  Au       0.203920000    0.087520000    0.305870000
  Au       0.305870000    0.087520000    0.203920000
  Au       0.000000000    0.175030000    0.203920000
  Au       0.101960000    0.175030000    0.305870000
  Au       0.101960000    0.262550000    0.203920000
  Au       0.000000000    0.820710000    0.101960000
  Au       0.101960000    0.733200000    0.101960000
  Au       0.101960000    0.820710000    0.000000000
  Au       0.203920000    0.820710000    0.101960000
  Au       0.101960000    0.645680000    0.203920000
  Au       0.000000000    0.820710000    0.305870000
  Au       0.101960000    0.733200000    0.305870000
  Au       0.101960000    0.820710000    0.203910000
  Au       0.203920000    0.733200000    0.203910000
  Au       0.203920000    0.820710000    0.305870000
  Au       0.305870000    0.820710000    0.203910000
  Au       0.101960000    0.909530000    0.101960000
  Au       0.000000000    0.909530000    0.203920000
  Au       0.203920000    0.909530000    0.203920000
  N        0.104560000    0.561910000    0.203540000
  N        0.104560000    0.346290000    0.203540000
  C        0.104560000    0.510410000    0.203540000
  C        0.104560000    0.454100000    0.203540000
  C        0.104560000    0.397790000    0.203540000
  ======================================================================
  Bond mid points [crystal]:
   10
  H        0.104560000    0.425945000    0.203540000   C  -- C
  H        0.104560000    0.482255000    0.203540000   C  -- C
  H        0.104560000    0.372040000    0.203540000   N  -- C
  H        0.104560000    0.536160000    0.203540000   N  -- C
  H        0.103260000    0.578045000    0.203730000   Au -- C
  H        0.103260000    0.603795000    0.203730000   Au -- N
  H        0.103260000    0.330170000    0.203730000   Au -- C
  H        0.103260000    0.304420000    0.203730000   Au -- N
  H        0.203920000   -0.045235000    0.203920000   Au -- Au
  H        0.000000000   -0.045235000    0.203920000   Au -- Au

  ======================================================================
   <global routines>
             clock number :     3
                 midpoint :     0.00s CPU

             want_dftread :     0.13s CPU
                want_init :

How can I get my wannier centers?


S.D.Wang
Southeast University in Najing ,China
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From sd.wang000 at gmail.com  Wed Apr  7 03:24:11 2010
From: sd.wang000 at gmail.com (shudong wang)
Date: Wed, 7 Apr 2010 09:24:11 +0800
Subject: [Wannier] disentangle.x
Message-ID: <q2lf82f94a11004061824o3cfe0544u224c906a91c4f65c@mail.gmail.com>

Dear developers.

I used disentangle.x code in WanT package do some calculation, but it stops
here

  ======================================================================
  =  Starting Iteration loop                                           =
  ======================================================================
  Initial trial subspace: projected localized orbitals
p0_13395:  p4_error: interrupt SIGx: 6

what is the problem?

I run it serial.
Thanks in advance!

S.D.Wang

Southeast University in Nanjing,China
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From lee0su at kist.re.kr  Wed Apr  7 06:33:25 2010
From: lee0su at kist.re.kr (Young-Su Lee)
Date: Wed, 7 Apr 2010 13:33:25 +0900
Subject: [Wannier] disentangle.x
In-Reply-To: <q2lf82f94a11004061824o3cfe0544u224c906a91c4f65c@mail.gmail.com>
References: <q2lf82f94a11004061824o3cfe0544u224c906a91c4f65c@mail.gmail.com>
Message-ID: <001201cad60b$7704fb80$650ef280$@re.kr>

Dear Shudong Wang,

 

This user-forum is for wannier90 not WanT.

Please redirect your questions to the WanT developers.

 

Young-Su

 

From: wannier-bounces at quantum-espresso.org
[mailto:wannier-bounces at quantum-espresso.org] On Behalf Of shudong wang
Sent: Wednesday, April 07, 2010 10:24 AM
To: wannier at quantum-espresso.org
Subject: [Wannier] disentangle.x

 

Dear developers.

 

I used disentangle.x code in WanT package do some calculation, but it stops
here

 

  ======================================================================
  =  Starting Iteration loop                                           =
  ======================================================================

  Initial trial subspace: projected localized orbitals
p0_13395:  p4_error: interrupt SIGx: 6

 

what is the problem?

 

I run it serial.

Thanks in advance!

 

S.D.Wang

 

Southeast University in Nanjing,China

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From elie.moujaes at hotmail.co.uk  Wed Apr  7 16:46:50 2010
From: elie.moujaes at hotmail.co.uk (Elie Moujaes)
Date: Wed, 7 Apr 2010 15:46:50 +0100
Subject: [Wannier] ab initio based Tight binding model
Message-ID: <SNT114-W333077E2AE545930245BAED3170@phx.gbl>


Dear Wannier90 users,

 

I have two simple questions:

 

(1)  What is the difference between the ab initio Tight binding model (derived using the Wannier90 localized functions) and the usual Tight binding model based on number of nearest or next nearest neighbours..etc?

 

(2) Would the band structure (say of graphene) differ using ab initio TB model (WANNIER90 code) from the one obtained using PW code although both start with self consistent calculations.

 

 

Regards

 

Elie Moujaes

University of Nottingham

NG7 2RD

UK 
 		 	   		  
_________________________________________________________________
http://clk.atdmt.com/UKM/go/195013117/direct/01/
We want to hear all your funny, exciting and crazy Hotmail stories. Tell us now
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From jonathan.yates at materials.ox.ac.uk  Wed Apr  7 19:24:41 2010
From: jonathan.yates at materials.ox.ac.uk (Jonathan Yates)
Date: Wed, 7 Apr 2010 18:24:41 +0100
Subject: [Wannier] ab initio based Tight binding model
In-Reply-To: <SNT114-W333077E2AE545930245BAED3170@phx.gbl>
References: <SNT114-W333077E2AE545930245BAED3170@phx.gbl>
Message-ID: <51B81FCD-9830-4CE8-86AE-2FE1BD76B185@materials.ox.ac.uk>


On 7 Apr 2010, at 15:46, Elie Moujaes wrote:

> Dear Wannier90 users,
>
> I have two simple questions:
>
> (1)  What is the difference between the ab initio Tight binding  
> model (derived using the Wannier90 localized functions) and the  
> usual Tight binding model based on number of nearest or next nearest  
> neighbours..etc?

In terms of the formalism, they are very similar.

The Wannier approach provides one way to obtain a set of TB matrix  
elements. The idea is to obtain the matrix elements such that the ab- 
initio results are reproduced for a given atomic configuration - even  
if this may require a large number of nearest neighbours.


>  (2) Would the band structure (say of graphene) differ using ab  
> initio TB model (WANNIER90 code) from the one obtained using PW code  
> although both start with self consistent calculations.

Figure 3 of Computer Physics Communications 178, 685 (2008) shows a  
comparison of a graphite band structure from W90 and from PWSCF.

In the limit of MLWF obtained from an ab-initio calculation with  
infinite k-point sampling they would be identical. At finite k-point  
sampling (ie any practical calculation) the band structures will  
differ - however, the difference will decrease exponentially as the k- 
point sampling is increased.

  This is discussed in Phys. Rev. B 75, 195121 (2007) - particularly  
the appendix.

Yours
   Jonathan

-- 
Department of Materials, University of Oxford, Parks Road, Oxford, OX1  
3PH, UK
tel: +44 (0)1865 612797                http://users.ox.ac.uk/~oums0549/



From elie.moujaes at hotmail.co.uk  Thu Apr  8 01:21:29 2010
From: elie.moujaes at hotmail.co.uk (Elie Moujaes)
Date: Thu, 8 Apr 2010 00:21:29 +0100
Subject: [Wannier] Ab initio based Tight binding model
Message-ID: <SNT114-W104952EAB73100490C405ED3170@phx.gbl>


Dear Prof Yates,

 

Thanks very much, as usual, for the clarification. I am actually trying to compare the band structure of both methods. When I have plotted the two curves (DFT based) and (ab initio TB based using WANNIER90), I realized that the K-point is displaced i.e, in both methods you get the same shape of the curves but in one of them they are at an earlier point (The K point is not the same in both). I looked at the both files and checked positions of atoms and positions of K and M points. I realised that in the .WIN file, the positions of the atoms were still in terms of the lattice vectors whereas they should be in cartesioan coordinates ( either angstroms or bohrs) so I did this correction but it did not seem to have solved the discrepancy. I will attach the ps file just to give you an idea of what i am talking about. Could you please, whenever possible, have a look at teh graph and tell what could have gone wrong.

 

 

Regards

 

Elie Moujaes

University of Nottingham

NG7 2RD

uk
 		 	   		  
_________________________________________________________________
http://clk.atdmt.com/UKM/go/195013117/direct/01/
We want to hear all your funny, exciting and crazy Hotmail stories. Tell us now
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From jonathan.yates at materials.ox.ac.uk  Thu Apr  8 10:16:03 2010
From: jonathan.yates at materials.ox.ac.uk (Jonathan Yates)
Date: Thu, 8 Apr 2010 09:16:03 +0100
Subject: [Wannier] Ab initio based Tight binding model
In-Reply-To: <SNT114-W104952EAB73100490C405ED3170@phx.gbl>
References: <SNT114-W104952EAB73100490C405ED3170@phx.gbl>
Message-ID: <2E8D7AF0-0041-4651-80C9-27C53BEBE4E7@materials.ox.ac.uk>


On 8 Apr 2010, at 00:21, Elie Moujaes wrote:

> Thanks very much, as usual, for the clarification. I am actually trying to compare the band structure of both methods. When I have plotted the two curves (DFT based) and (ab initio TB based using WANNIER90), I realized that the K-point is displaced i.e, in both methods you get the same shape of the curves but in one of them they are at an earlier point (The K point is not the same in both). I looked at the both files and checked positions of atoms and positions of K and M points. I realised that in the .WIN file, the positions of the atoms were still in terms of the lattice vectors whereas they should be in cartesioan coordinates ( either angstroms or bohrs) so I did this correction but it did not seem to have solved the discrepancy. I will attach the ps file just to give you an idea of what i am talking about. Could you please, whenever possible, have a look at teh graph and tell what could have gone wrong.

The answer is pretty straight-forward:
  Think about what the x-axis should be - in the wannier90 plot it is the distance along the recip space path (in inverse Angstroms). For the pwscf bands you've used a different scale.

 Either figure out what the correct x-axis should be (I think in this case the missing factor is 2*pi/a=2.46 but in general it is more complicated), or, if you have used the same kpoints for both calculations you can just take the x-axis scale from the wannier90 calculation.

 Yours
  Jonathan


-- 
Department of Materials, University of Oxford, Parks Road, Oxford, OX1 3PH, UK
tel: +44 (0)1865 612797                http://users.ox.ac.uk/~oums0549/



From elie.moujaes at hotmail.co.uk  Thu Apr  8 15:20:15 2010
From: elie.moujaes at hotmail.co.uk (Elie Moujaes)
Date: Thu, 8 Apr 2010 14:20:15 +0100
Subject: [Wannier] Ab initio based Tight binding model
Message-ID: <SNT114-W21D3A0BD9DC56BEED6EC93D3160@phx.gbl>


Dear prof. Yates,

 

Thanks again for the clarification. I was not aware of this difference in scale thing. Of course by just looking at the plots, you can figure out that there is a misplacement because the energies are the same but the x axis positions are not. Is there anywhere I can read more about this scale difference because I looked at the output of both W90 and PWSCF and found that the poisitions of the atoms in cartesian coordinates are the same so I am not quite sure where does it show that there is a difference in the scale of the x axis in both methods.

 

P.S: I did use the same k-points in both.

 

Thank you again and sorry for disturbing you.

 

 

Regards

 

Elie
 		 	   		  
_________________________________________________________________
http://clk.atdmt.com/UKM/go/195013117/direct/01/
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From jonathan.yates at materials.ox.ac.uk  Thu Apr  8 23:12:32 2010
From: jonathan.yates at materials.ox.ac.uk (Jonathan Yates)
Date: Thu, 8 Apr 2010 22:12:32 +0100
Subject: [Wannier] Ab initio based Tight binding model
In-Reply-To: <SNT114-W21D3A0BD9DC56BEED6EC93D3160@phx.gbl>
References: <SNT114-W21D3A0BD9DC56BEED6EC93D3160@phx.gbl>
Message-ID: <658A1062-55DE-4AF4-ABAE-DEC33E718B90@materials.ox.ac.uk>


On 8 Apr 2010, at 14:20, Elie Moujaes wrote:

> Thanks again for the clarification. I was not aware of this difference in scale thing. Of course by just looking at the plots, you can figure out that there is a misplacement because the energies are the same but the x axis positions are not. Is there anywhere I can read more about this scale difference because I looked at the output of both W90 and PWSCF and found that the poisitions of the atoms in cartesian coordinates are the same so I am not quite sure where does it show that there is a difference in the scale of the x axis in both methods.

 Let me describe a simplified version of the problem you are trying to understand: You have two kpoints. By convention we express the kpoints in terms of the reciprocal lattice vectors. However, to make a bandstructure plot we  want to know the distance between the two kpoints (a suitable unit would be inverse angstroms). If the cell is orthorhombic the conversion is trivial - for a general cell it's also a simple problem but might involve more math. I suggestion reading Chapter 4 of Richard Martin's book 'Electronic Structure'. Note the discussion starting at the end of page 83 regarding finding lengths in real and reciprocal space. He introduces the real and recip space metric - if you look in the wannier90 source code (plot.F90) you'll find we adopted a similar notation.

 Yours
  Jonathan




-- 
Department of Materials, University of Oxford, Parks Road, Oxford, OX1 3PH, UK
tel: +44 (0)1865 612797                http://users.ox.ac.uk/~oums0549/



From janfelix.binder at epfl.ch  Fri Apr  9 18:02:37 2010
From: janfelix.binder at epfl.ch (Jan Felix Binder)
Date: Fri, 09 Apr 2010 18:02:37 +0200
Subject: [Wannier] Wannier function centers at wrong positions
Message-ID: <4BBF4F9D.2050305@epfl.ch>

Hello,
I used the W90 code with PWscf (QE 4.1.2) to calculate MLWF for a 
amorphous structure (gamma point only, 234 atoms, 606 wf).
All WF convered to reasonable values. Most of the centers are at the 
right positions, but approximately 10 centers hang somewhere around.
What can be wrong?

I add the imported lines of the input file:
 gamma_only = .true.
num_iter         =  100
dis_num_iter     =  200
conv_window = 10
conv_noise_amp = 1
conv_noise_num = 10
dis_mix_ratio = 0.3
guiding_centres = .true.

iprint           =    2
num_dump_cycles  =   10
num_print_cycles =   10

length_unit      =  Ang

num_wann = 606
num_bands=606

exclude_bands : 607-614

Begin Projections
random
End Projections

translate_home_cell=.true.
write_xyz=.true.

begin unit_cell_cart
 bohr
47.65304  0.00000  0.00000
 0.00000 23.82652  0.00000
 0.00000  0.00000 23.82652
end unit_cell_cart

Thank you for help!
Felix Binder

EPFL Lausanne


From poilvert at mit.edu  Fri Apr  9 18:22:13 2010
From: poilvert at mit.edu (nicolas poilvert)
Date: Fri, 9 Apr 2010 12:22:13 -0400
Subject: [Wannier] Wannier function centers at wrong positions
In-Reply-To: <4BBF4F9D.2050305@epfl.ch>
References: <4BBF4F9D.2050305@epfl.ch>
Message-ID: <g2u66bc743b1004090922n399c404fw2f9d3187b722878e@mail.gmail.com>

Dear Jan,

I see that in your input file that you use exactly 606 bands for 606 Wannier
Functions.
It would be good to maybe include more bands in your calculation and use the
disentanglement
procedure (look at the Wannier User Guide for that).
Also, if you cell is quite big, using random projections may not be optimal.
So if you have an
idea of what those Wannier Functions should be, there is definitely
advantage to input some
carefully chosen initial projections. In the random guess case, the code may
get stuck in a local
minimum that does not correspond to the proper physical minimum you seek.
As a final note, I would set the convergence threshold to 1.0d-7 at least to
both disentanglement
and wannierisation and use a lot of steps just in case (num_iter > 2000 and
dis_num_iter > 2000).

good luck,

Nicolas

On Fri, Apr 9, 2010 at 12:02 PM, Jan Felix Binder
<janfelix.binder at epfl.ch>wrote:

> Hello,
> I used the W90 code with PWscf (QE 4.1.2) to calculate MLWF for a
> amorphous structure (gamma point only, 234 atoms, 606 wf).
> All WF convered to reasonable values. Most of the centers are at the
> right positions, but approximately 10 centers hang somewhere around.
> What can be wrong?
>
> I add the imported lines of the input file:
>  gamma_only = .true.
> num_iter         =  100
> dis_num_iter     =  200
> conv_window = 10
> conv_noise_amp = 1
> conv_noise_num = 10
> dis_mix_ratio = 0.3
> guiding_centres = .true.
>
> iprint           =    2
> num_dump_cycles  =   10
> num_print_cycles =   10
>
> length_unit      =  Ang
>
> num_wann = 606
> num_bands=606
>
> exclude_bands : 607-614
>
> Begin Projections
> random
> End Projections
>
> translate_home_cell=.true.
> write_xyz=.true.
>
> begin unit_cell_cart
>  bohr
> 47.65304  0.00000  0.00000
>  0.00000 23.82652  0.00000
>  0.00000  0.00000 23.82652
> end unit_cell_cart
>
> Thank you for help!
> Felix Binder
>
> EPFL Lausanne
> _______________________________________________
> Wannier mailing list
> Wannier at quantum-espresso.org
> http://www.democritos.it/mailman/listinfo/wannier
>



-- 
POILVERT Nicolas
PhD candidate,
Dpt of Materials Science and Engineering
Massachusetts Institute of Technology
77, Massachusetts avenue
Cambridge, MA 02139
USA
work: (617) 452-4212
nicolas.poilvert at gmail.com
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From jonathan.yates at materials.ox.ac.uk  Fri Apr  9 18:58:58 2010
From: jonathan.yates at materials.ox.ac.uk (Jonathan Yates)
Date: Fri, 9 Apr 2010 17:58:58 +0100
Subject: [Wannier] Wannier function centers at wrong positions
In-Reply-To: <g2u66bc743b1004090922n399c404fw2f9d3187b722878e@mail.gmail.com>
References: <4BBF4F9D.2050305@epfl.ch>
	<g2u66bc743b1004090922n399c404fw2f9d3187b722878e@mail.gmail.com>
Message-ID: <23440D73-010B-49F8-B683-ADECF17F362E@materials.ox.ac.uk>

Jan,

 I just wanted to add a few things to Nicolas's reply:

Given that you are using the Gamma-point only routines and your cell is orthorhombic I would expect that any initial projection would work fine - and the minimisation would go rapidly to the minimum. Of course you can test this statement by trying different projections. If you find this not to be true I'd be interested to know.

I assume that you want MLWF to analyse some bonding properties of your material. A common task would be to obtain MLWF for the complete set of valence states (I'm assuming here that your material has a gap). In which case 606 MLWF for 234 atoms seems rather low (so for 234 atoms of SiO2 or GeO2 we'd have 1872 MLWF).
  Are you trying to obtain MWLF for a subset of the valence bands? This will only work if those 606 bands form an isolated set. If not you have to look into the disentanglement routines.

'centers hang somewhere around'
  I'm not quite sure what you mean by this. I assume it is not something as simple as needing to translate by a lattice vector? 

Hopefully that has given you some things to try. I think to make any more comments I'd need to see the *.wout file, and know a bit more about your system.

 Yours
  Jonathan


  



On 9 Apr 2010, at 17:22, nicolas poilvert wrote:

> Dear Jan,
> 
> I see that in your input file that you use exactly 606 bands for 606 Wannier Functions.
> It would be good to maybe include more bands in your calculation and use the disentanglement
> procedure (look at the Wannier User Guide for that).
> Also, if you cell is quite big, using random projections may not be optimal. So if you have an
> idea of what those Wannier Functions should be, there is definitely advantage to input some
> carefully chosen initial projections. In the random guess case, the code may get stuck in a local
> minimum that does not correspond to the proper physical minimum you seek.
> As a final note, I would set the convergence threshold to 1.0d-7 at least to both disentanglement
> and wannierisation and use a lot of steps just in case (num_iter > 2000 and dis_num_iter > 2000).
> 
> good luck,
> 
> Nicolas
> 
> On Fri, Apr 9, 2010 at 12:02 PM, Jan Felix Binder <janfelix.binder at epfl.ch> wrote:
> Hello,
> I used the W90 code with PWscf (QE 4.1.2) to calculate MLWF for a
> amorphous structure (gamma point only, 234 atoms, 606 wf).
> All WF convered to reasonable values. Most of the centers are at the
> right positions, but approximately 10 centers hang somewhere around.
> What can be wrong?
> 
> I add the imported lines of the input file:
>  gamma_only = .true.
> num_iter         =  100
> dis_num_iter     =  200
> conv_window = 10
> conv_noise_amp = 1
> conv_noise_num = 10
> dis_mix_ratio = 0.3
> guiding_centres = .true.
> 
> iprint           =    2
> num_dump_cycles  =   10
> num_print_cycles =   10
> 
> length_unit      =  Ang
> 
> num_wann = 606
> num_bands=606
> 
> exclude_bands : 607-614
> 
> Begin Projections
> random
> End Projections
> 
> translate_home_cell=.true.
> write_xyz=.true.
> 
> begin unit_cell_cart
>  bohr
> 47.65304  0.00000  0.00000
>  0.00000 23.82652  0.00000
>  0.00000  0.00000 23.82652
> end unit_cell_cart
> 
> Thank you for help!
> Felix Binder
> 
> EPFL Lausanne

-- 
Department of Materials, University of Oxford, Parks Road, Oxford, OX1 3PH, UK
tel: +44 (0)1865 612797                http://users.ox.ac.uk/~oums0549/



From gianluca.giovannetti at gmail.com  Tue Apr 13 15:08:05 2010
From: gianluca.giovannetti at gmail.com (Gianluca Giovannetti)
Date: Tue, 13 Apr 2010 15:08:05 +0200
Subject: [Wannier] Wannier functions of molecular crystal
Message-ID: <r2n7234ba151004130608o9bcb296dle0ccf841447192@mail.gmail.com>

Dear All,

i`m calculating Wannier functions for a molecular crystal (sites are
molecule with C and H ions within each molecule).

i want to plot Wannier functions of the 4 bands at Fermi level.
the system is metallic.
these four bands come from HOMO and LUMO molecular states of the two
inequivalent molecules in the unit cell.

here it is my input file:

--------------------------------

num_wann        = 4
num_iter        = 2000

dis_num_iter    =  500

iprint = 3

!here we exclude all bands except the O2p bands
exclude_bands : 1-126,131-180

!bands_plot_project : 1,2,3,4

write_r2mn=.true.
hr_plot=.true.

kmesh_tol=0.00001

begin atoms_cart
ang
[......]
end atoms_cart

begin kpoint_path
G 0.00000000 0.00000000 0.00000000    M  0.50000000 0.00000000 0.00000000
M 0.50000000 0.00000000 0.00000000    X  0.50000000 0.50000000 0.00000000
X 0.50000000 0.50000000 0.00000000    G  0.50000000 0.00000000 0.50000000
G 0.50000000 0.00000000 0.50000000    Z  0.00000000 0.00000000 0.00000000
Z 0.00000000 0.00000000 0.00000000    R  0.50000000 0.50000000 0.00000000
R 0.50000000 0.50000000 0.00000000    A  0.50000000 0.00000000 0.50000000
A 0.50000000 0.00000000 0.50000000    Z  0.50000000 0.50000000 0.50000000
Z 0.50000000 0.50000000 0.50000000    C  0.50000000 0.00000000 0.00000000
C 0.50000000 0.00000000 0.00000000    F  0.50000000 0.50000000 0.00000000
end kpoint_path
bands_plot =T

!fermi_surface_plot = .true.

!To plot the WF
!wannier_plot = T
!wannier_plot_supercell = 2
!wannier_plot_list = 1 2 3 4
!restart = plot

guiding_centres = T

begin projections
random
end projections


begin unit_cell_cart
bohr
16.4538 0.000 0.000
0.000 0.000 -11.172
-1.18447 24.481 0.000
end unit_cell_cart

mp_grid : 8 8 8

begin kpoints
[...]
end kpoints


--------------------------------

However i get Wannier eigenvalues which are not exactly the same as the one
i have calculated Quantum espresso (the discrepancy is not big but finite at
some k-points).

My feeling is that the setting in the win file:

begin projections
random
end projections

is not really good as starting point.

Indeed the CONV is 1.0E-03.

HOMO and LUMO are localized on the molecules.

What is the best strategy in this case?

thank you in advance.

Gianluca
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From jonathan.yates at materials.ox.ac.uk  Tue Apr 13 23:48:12 2010
From: jonathan.yates at materials.ox.ac.uk (Jonathan Yates)
Date: Tue, 13 Apr 2010 22:48:12 +0100
Subject: [Wannier] Wannier functions of molecular crystal
In-Reply-To: <r2n7234ba151004130608o9bcb296dle0ccf841447192@mail.gmail.com>
References: <r2n7234ba151004130608o9bcb296dle0ccf841447192@mail.gmail.com>
Message-ID: <8A882CFC-1174-477D-97B7-26E5D87F8F9B@materials.ox.ac.uk>


On 13 Apr 2010, at 14:08, Gianluca Giovannetti wrote:

Dear All,

i`m calculating Wannier functions for a molecular crystal (sites are molecule with C and H ions within each molecule).

i want to plot Wannier functions of the 4 bands at Fermi level.
the system is metallic.
these four bands come from HOMO and LUMO molecular states of the two inequivalent molecules in the unit cell.

Gianluca,

 I'm assuming that these four bands which span the fermi level form an isolated group (so no disentanglement is needed)


My feeling is that the setting in the win file:
begin projections
random
end projections
is not really good as starting point.
Indeed the CONV is 1.0E-03.
HOMO and LUMO are localized on the molecules.
What is the best strategy in this case?

I think using randomly placed Gaussian functions is likely to be particularly bad in this case. If the orbitals are already fairly localised, and the cell is pretty large, then the trial functions might have little overlap with the bloch states. That won't make the calculation wrong - just that the starting point could be poor.
 So if you think that the states are 2p like on Oxygen then try such projections as a starting guess. Sometimes a two-step procedure might help: look at the WF resulting from the random projections - if they appear to have some symmetry character then try again using a projection of that form.

 It might help in this procedure to use a coarser kpoint mesh (4x4x4 or even 2x2x2) - I find that the minimiser can cope better with a poor starting guess in this case. Then when I know what the MLWF should look like, I increase the mesh.

However i get Wannier eigenvalues which are not exactly the same as the one i have calculated Quantum espresso (the discrepancy is not big but finite at some k-points).

 You're obtaining the band-structure by interpolation. At the kpoints which lie in the original (ab-initio) grid the energies will be reproduced exactly. At any other points it is an interpolation. Importantly the quality of the interpolation increases exponentially as the size of kpoint mesh is increased.
 However, it is probably a good plan to get well localised wannier functions first - as this may improve the interpolation.

 Jonathan




--
Department of Materials, University of Oxford, Parks Road, Oxford, OX1 3PH, UK
tel: +44 (0)1865 612797                http://users.ox.ac.uk/~oums0549/

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From gianluca.giovannetti at gmail.com  Wed Apr 14 08:29:25 2010
From: gianluca.giovannetti at gmail.com (Gianluca Giovannetti)
Date: Wed, 14 Apr 2010 08:29:25 +0200
Subject: [Wannier] Wannier functions of molecular crystal
In-Reply-To: <8A882CFC-1174-477D-97B7-26E5D87F8F9B@materials.ox.ac.uk>
References: <r2n7234ba151004130608o9bcb296dle0ccf841447192@mail.gmail.com>
	<8A882CFC-1174-477D-97B7-26E5D87F8F9B@materials.ox.ac.uk>
Message-ID: <y2h7234ba151004132329s7837dbdbv5120c30484e60996@mail.gmail.com>

Dear Jonathan,

thank you for your reply.

I think the symmetry of the WFs should be of p character.

I have however one problem.
I have 4 bands.
The number of Carbon ions in one molecule is 22 (and there are 2 molecules).

How can i set the flags:

begin projections

end projections

in such case in order to avoid the code messagge: "param_get_projection: too
many projections defined"?

ciao

G.


On Tue, Apr 13, 2010 at 11:48 PM, Jonathan Yates <
jonathan.yates at materials.ox.ac.uk> wrote:

>
> On 13 Apr 2010, at 14:08, Gianluca Giovannetti wrote:
>
> Dear All,
>
> i`m calculating Wannier functions for a molecular crystal (sites are
> molecule with C and H ions within each molecule).
>
> i want to plot Wannier functions of the 4 bands at Fermi level.
> the system is metallic.
> these four bands come from HOMO and LUMO molecular states of the two
> inequivalent molecules in the unit cell.
>
>
> Gianluca,
>
>  I'm assuming that these four bands which span the fermi level form an
> isolated group (so no disentanglement is needed)
>
>
> My feeling is that the setting in the win file:
> begin projections
> random
> end projections
> is not really good as starting point.
> Indeed the CONV is 1.0E-03.
> HOMO and LUMO are localized on the molecules.
> What is the best strategy in this case?
>
>
> I think using randomly placed Gaussian functions is likely to be
> particularly bad in this case. If the orbitals are already fairly localised,
> and the cell is pretty large, then the trial functions might have little
> overlap with the bloch states. That won't make the calculation wrong - just
> that the starting point could be poor.
>  So if you think that the states are 2p like on Oxygen then try such
> projections as a starting guess. Sometimes a two-step procedure might help:
> look at the WF resulting from the random projections - if they appear to
> have some symmetry character then try again using a projection of that form.
>
>  It might help in this procedure to use a coarser kpoint mesh (4x4x4 or
> even 2x2x2) - I find that the minimiser can cope better with a poor starting
> guess in this case. Then when I know what the MLWF should look like, I
> increase the mesh.
>
> However i get Wannier eigenvalues which are not exactly the same as the one
> i have calculated Quantum espresso (the discrepancy is not big but finite at
> some k-points).
>
>
>  You're obtaining the band-structure by interpolation. At the kpoints which
> lie in the original (ab-initio) grid the energies will be reproduced
> exactly. At any other points it is an interpolation. Importantly the quality
> of the interpolation increases exponentially as the size of kpoint mesh is
> increased.
>  However, it is probably a good plan to get well localised wannier
> functions first - as this may improve the interpolation.
>
>  Jonathan
>
>
>
>
> --
> Department of Materials, University of Oxford, Parks Road, Oxford, OX1 3PH,
> UK
> tel: +44 (0)1865 612797                http://users.ox.ac.uk/~oums0549/<http://users.ox.ac.uk/%7Eoums0549/>
>
>
> _______________________________________________
> Wannier mailing list
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From jonathan.yates at materials.ox.ac.uk  Wed Apr 14 11:00:39 2010
From: jonathan.yates at materials.ox.ac.uk (Jonathan Yates)
Date: Wed, 14 Apr 2010 10:00:39 +0100
Subject: [Wannier] Wannier functions of molecular crystal
In-Reply-To: <y2h7234ba151004132329s7837dbdbv5120c30484e60996@mail.gmail.com>
References: <r2n7234ba151004130608o9bcb296dle0ccf841447192@mail.gmail.com>
	<8A882CFC-1174-477D-97B7-26E5D87F8F9B@materials.ox.ac.uk>
	<y2h7234ba151004132329s7837dbdbv5120c30484e60996@mail.gmail.com>
Message-ID: <2689D717-711F-4D68-A68D-7C600038DC45@materials.ox.ac.uk>


On 14 Apr 2010, at 07:29, Gianluca Giovannetti wrote:

> Dear Jonathan,
> 
> thank you for your reply. 
> 
> I think the symmetry of the WFs should be of p character.
> 
> I have however one problem.
> I have 4 bands.
> The number of Carbon ions in one molecule is 22 (and there are 2 molecules).
> 
> How can i set the flags:
> 
> begin projections
> 
> end projections
> 
> in such case in order to avoid the code messagge: "param_get_projection: too many projections defined"?

Gianluca,
 
The short cut notion
C:pz
 would put a single p orbital on all C sites - so would lead to the error you describe.

To specify a p_z orbital on a single site you can use fraction or cartesian coordinates
 eg f=0,0.50,0:pz
Alternatively if you give the atoms on which you want to have projections a different name in the atom list eg 'C1' then you can just do C1:pz (see example10 - and Chapter 3 of the user guide)

 Yours
  Jonathan




-- 
Department of Materials, University of Oxford, Parks Road, Oxford, OX1 3PH, UK
tel: +44 (0)1865 612797                http://users.ox.ac.uk/~oums0549/



From gianluca.giovannetti at gmail.com  Wed Apr 14 14:39:06 2010
From: gianluca.giovannetti at gmail.com (Gianluca Giovannetti)
Date: Wed, 14 Apr 2010 14:39:06 +0200
Subject: [Wannier] Wannier functions of molecular crystal
In-Reply-To: <2689D717-711F-4D68-A68D-7C600038DC45@materials.ox.ac.uk>
References: <r2n7234ba151004130608o9bcb296dle0ccf841447192@mail.gmail.com>
	<8A882CFC-1174-477D-97B7-26E5D87F8F9B@materials.ox.ac.uk>
	<y2h7234ba151004132329s7837dbdbv5120c30484e60996@mail.gmail.com>
	<2689D717-711F-4D68-A68D-7C600038DC45@materials.ox.ac.uk>
Message-ID: <u2i7234ba151004140539qa5367bf8m52af134c8ef714c2@mail.gmail.com>

Dear Jonathan,

thank you for the reply.

I think i have still some troubles to understand how to give a good starting
guess. :-)

Please let look at this paper:

J. Phys. Soc. Jpn. *78* <http://jpsj.ipap.jp/archive/JPSJ-78.html> (2009)
113704

and let think we want to reproduce exactly the WFs in their Fig. 3.

As you can see the Wannier functions are localized over all the molecule and
they look like some linear combination of p states over all the C and H
ions.

Is the option " f=0,0.50,0:pz" a good starting guess?
Is the latter option the best i can use in such case?

ciao

G.


On Wed, Apr 14, 2010 at 11:00 AM, Jonathan Yates <
jonathan.yates at materials.ox.ac.uk> wrote:

>
> On 14 Apr 2010, at 07:29, Gianluca Giovannetti wrote:
>
> > Dear Jonathan,
> >
> > thank you for your reply.
> >
> > I think the symmetry of the WFs should be of p character.
> >
> > I have however one problem.
> > I have 4 bands.
> > The number of Carbon ions in one molecule is 22 (and there are 2
> molecules).
> >
> > How can i set the flags:
> >
> > begin projections
> >
> > end projections
> >
> > in such case in order to avoid the code messagge: "param_get_projection:
> too many projections defined"?
>
> Gianluca,
>
> The short cut notion
> C:pz
>  would put a single p orbital on all C sites - so would lead to the error
> you describe.
>
> To specify a p_z orbital on a single site you can use fraction or cartesian
> coordinates
>  eg f=0,0.50,0:pz
> Alternatively if you give the atoms on which you want to have projections a
> different name in the atom list eg 'C1' then you can just do C1:pz (see
> example10 - and Chapter 3 of the user guide)
>
>  Yours
>   Jonathan
>
>
>
>
> --
> Department of Materials, University of Oxford, Parks Road, Oxford, OX1 3PH,
> UK
> tel: +44 (0)1865 612797                http://users.ox.ac.uk/~oums0549/<http://users.ox.ac.uk/%7Eoums0549/>
>
> _______________________________________________
> Wannier mailing list
> Wannier at quantum-espresso.org
> http://www.democritos.it/mailman/listinfo/wannier
>
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From jonathan.yates at materials.ox.ac.uk  Thu Apr 15 01:32:55 2010
From: jonathan.yates at materials.ox.ac.uk (Jonathan Yates)
Date: Thu, 15 Apr 2010 00:32:55 +0100
Subject: [Wannier] Wannier functions of molecular crystal
In-Reply-To: <u2i7234ba151004140539qa5367bf8m52af134c8ef714c2@mail.gmail.com>
References: <r2n7234ba151004130608o9bcb296dle0ccf841447192@mail.gmail.com>
	<8A882CFC-1174-477D-97B7-26E5D87F8F9B@materials.ox.ac.uk>
	<y2h7234ba151004132329s7837dbdbv5120c30484e60996@mail.gmail.com>
	<2689D717-711F-4D68-A68D-7C600038DC45@materials.ox.ac.uk>
	<u2i7234ba151004140539qa5367bf8m52af134c8ef714c2@mail.gmail.com>
Message-ID: <BFC7C7B4-F340-4678-A024-28588EFE2E54@materials.ox.ac.uk>


On 14 Apr 2010, at 13:39, Gianluca Giovannetti wrote:

> Dear Jonathan,
> 
> thank you for the reply.
> 
> I think i have still some troubles to understand how to give a good starting guess. :-)
> 
> Please let look at this paper:
> 
> J. Phys. Soc. Jpn. 78 (2009) 113704 
> 
> and let think we want to reproduce exactly the WFs in their Fig. 3.
> 
> As you can see the Wannier functions are localized over all the molecule and they look like some linear combination of p states over all the C and H ions.

Those WF are quite extended - which is not so surprising given the Bloch states they correspond to.

 I admit I am not sure what the best projection would be. Experiment! (maybe pick an atom in the middle and but a pz on it?). Remember the projection is just a starting guess - it should not be too critical. Maybe run the wannierisation for a large number of steps.
 As your cell is quite large you might try gamma point and the gamma only routines, the bandstructure won't be good - but the MLFW might have the same form as for better kpoint samplings. Gamma point is the most robust minimisation scheme (it is a much simpler problem)


> Is the option " f=0,0.50,0:pz" a good starting guess?
> Is the latter option the best i can use in such case?

 No - it was just an example to demonstrate the syntax, nothing to do with your system.

 Jonathan


-- 
Department of Materials, University of Oxford, Parks Road, Oxford, OX1 3PH, UK
tel: +44 (0)1865 612797                http://users.ox.ac.uk/~oums0549/