[Pw_forum] question about elphonon calculation

Mozahar Ali mozaharphysics25 at yahoo.com
Sun May 17 17:49:17 CEST 2009


Dear all userI feel problem to calculate electron-phonon interaction with q-points.How can I choose the q-point mesh?The elph.output result is giving the error messegs as q- is not a vector in the dense grid.My scf,scf.fit and elph.in input files are given below and the last page of elph.out output also given.At first I run the scf.in and then scf.fit.in and finally elph.in.My sample is a superhard material.scf input: &control
    prefix='BC5'
     restart_mode='from_scratch',
    calculation = 'scf'
    pseudo_dir = '/Thesis2007/espresso-3.1.1/pseudo'
    outdir='/Thesis2007/temp'
    tprnfor=.true.
    tstress = .true.
 /
 &system    
    ibrav=  4, celldm(1)=4.825803501, celldm(3)=2.5056, nat=6, ntyp= 2,
    ecutwfc =35.0, ecutrho=150.0,
    occupations='smearing', smearing='m-v',degauss =0.01,
 /
 &electrons
   diagonalization= 'cg' ,
    mixing_mode = 'plain'
    mixing_beta = 0.7
    conv_thr =  1.0d-8
 /
ATOMIC_SPECIES
B  10.81000   B.pw91-n-van_ak.UPF 
C  12.0107    C.pw91-van_ak.UPF
ATOMIC_POSITIONS {crystal}
  B      0.000000000    0.000000000    0.007000000    
  C      0.000000000    0.000000000    0.259200000    
  C      0.333333300   -0.333333300    0.338600000
  C      0.333333300   -0.333333300    0.581600000
  C      0.666666667   -0.666666667    0.664600000
  C      0.666666667   -0.666666667    0.899900000    
 K_POINTS automatic 
 9 9 4 0 0 0

scf.fit input:
 &control
    calculation ='scf'
    restart_mode='from_scratch',
    prefix='BC5'
    pseudo_dir = '/Thesis2007/espresso-3.1.1/pseudo'
    outdir='/Thesis2007/temp'
 /
 &system    
    ibrav=  4, a=2.5537,  c=6.3985, nat=6, ntyp= 2,
    ecutwfc =35.0, ecutrho=150.0,
    occupations='smearing', smearing='methfessel-paxton', degauss=0.01,
    la2F = .true., 
 /
 &electrons
    mixing_beta = 0.7
    conv_thr =  1.0d-8
 /
ATOMIC_SPECIES
B  10.81000   B.pw91-n-van_ak.UPF 
C  12.0107    C.pw91-van_ak.UPF
ATOMIC_POSITIONS {crystal}
  B      0.000000000    0.000000000    0.007000000    
  C      0.000000000    0.000000000    0.259200000    
  C      0.333333300   -0.333333300    0.338600000
  C      0.333333300   -0.333333300    0.581600000
  C      0.666666667   -0.666666667    0.664600000
  C      0.666666667   -0.666666667    0.899900000    
K_POINTS automatic 
11 11 4 0 0 0


elph. input:
    Electron-phonon coefficients for BC5
 &inputph
  tr2_ph=1.0d-10,
  prefix='BC5',
  fildvscf='BC5dv',
  amass(1)=10.810,
  amass(2)=12.0107
  outdir='/Thesis2007/temp'
  fildyn='BC5.dyn',
  elph=.true.,
  trans=.true.,
  ldisp=.true.
  nq1=2, nq2=2, nq3=3,
 /Last page of elph. output:     Convergence has been achieved 
 
     Number of q in the star =    1
     List of q in the star:
          1   0.000000000   0.000000000   0.133036389
     In addition there is the -q list: 
          1 0.000000000 0.000000000-0.133036389

     Diagonalizing the dynamical matrix

     q = (    0.000000000   0.000000000   0.133036389 ) 

 **************************************************************************
     omega( 1) =       5.505487 [THz] =     183.644514 [cm-1]
     omega( 2) =       5.505487 [THz] =     183.644514 [cm-1]
     omega( 3) =       8.997032 [THz] =     300.110679 [cm-1]
     omega( 4) =      10.179023 [THz] =     339.537920 [cm-1]
     omega( 5) =      10.179023 [THz] =     339.537920 [cm-1]
     omega( 6) =      15.641133 [THz] =     521.735520 [cm-1]
     omega( 7) =      15.641133 [THz] =     521.735520 [cm-1]
     omega( 8) =      17.156151 [THz] =     572.271403 [cm-1]
     omega( 9) =      22.199800 [THz] =     740.510529 [cm-1]
     omega(10) =      22.199800 [THz] =     740.510529 [cm-1]
     omega(11) =      26.623991 [THz] =     888.086643 [cm-1]
     omega(12) =      29.688222 [THz] =     990.299072 [cm-1]
     omega(13) =      30.654823 [THz] =    1022.541636 [cm-1]
     omega(14) =      30.654823 [THz] =    1022.541636 [cm-1]
     omega(15) =      32.111991 [THz] =    1071.147834 [cm-1]
     omega(16) =      32.111991 [THz] =    1071.147834 [cm-1]
     omega(17) =      32.709423 [THz] =    1091.076164 [cm-1]
     omega(18) =      34.735445 [THz] =    1158.657439 [cm-1]
 **************************************************************************
     electron-phonon interaction  ...


 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
     from elphsum : error #         3
     q is not a vector in the dense grid
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

     stopping ...







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