[QE-users] Problems generating copper XANES

[Anders Hutcheson]

Dear everybody,

I have been trying to generate XANES-spectra for copper covalently incorporated into the framework of the zeotype, SAPO-34. Copper in these structures are covalently bound to 4 oxygen atoms and is assumed to be divalent. The calculated XANES that i obtained look very little like the XANES of copper and in some cases a sharp peak occurs at 0eV. I'm unfamiliar with XSPECTRA and QE in general, so I'm not sure what's wrong.

To obtained these specra I first generated two ultrasoft(US) pseudopotentials(PP), with and without a core hole. I then did the scf calculation, using a geometry optimized unit cell containing 1 Cu, using the copper PP with a core hole. The core wavefunction was extracted from the copper PP without a core hole. Finally the XANES was generated. In addition, I have also tried using NC PP, but the results were still poor.

Below you can see the input for the generation of PP, SCF-calculation and XANES generation. Any comment or help would be much appreciated.

Best regards

Anders Hutcheson

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

------PP-generation without core hole:

  &input
    title='Cu',
    zed=29.,
    rel=1,
    config='[Ar] 3d9.5 4s1.5 4p0.0',
    iswitch=3,
    dft='PBE'
  /
  &inputp
    lpaw=.true.,
    pseudotype=3,
    file_pseudopw='Cu.pbe-dn-kjpaw_psl.0.2.UPF',
    author='ADC',
    lloc=-1,
    rcloc=1.9,
    which_augfun='BESSEL',
    rmatch_augfun=1.8,
    nlcc=.true.,
    rcore=0.7,
    tm=.true.
    lgipaw_reconstruction=.true.
    use_paw_as_gipaw=.true.
  /
6
4S  1  0  1.50  0.00  2.20  2.30  0.0
4S  1  0  0.00  6.10  1.40  2.30  0.0
4P  2  1  0.00  0.00  2.20  2.30  0.0
4P  2  1  0.00  6.30  1.40  2.30  0.0
3D  3  2  9.50  0.00  1.50  1.90  0.0
3D  3  2  0.00  2.30  1.50  1.90  0.0

------PP-generation with core hole:

  &input
    title='Cu',
    zed=29.,
    rel=1,
    config='1s1 2s2 2p6 3s2 3p6 3d9.5 4s1.5 4p0.0',
    iswitch=3,
    dft='PBE'
  /
  &inputp
    lpaw=.true.,
    pseudotype=3,
    file_pseudopw='Cuh.pbe-dn-kjpaw_psl.0.2.UPF',
    author='ADC',
    lloc=-1,
    rcloc=1.9,
    which_augfun='BESSEL',
    rmatch_augfun=1.8,
    nlcc=.true.,
    rcore=0.7,
    tm=.true.
    lgipaw_reconstruction=.true.
    use_paw_as_gipaw=.true.
  /
6
4S  1  0  1.50  0.00  2.20  2.30  0.0
4S  1  0  0.00  6.10  1.40  2.30  0.0
4P  2  1  0.00  0.00  2.20  2.30  0.0
4P  2  1  0.00  6.30  1.40  2.30  0.0
3D  3  2  9.50  0.00  1.50  1.90  0.0
3D  3  2  0.00  2.30  1.50  1.90  0.0

------ SCF-input:

     calculation='scf',
     pseudo_dir ='./'
     prefix='SAPO',
  /
  &system
     ibrav=  14,
     celldm(1) = 17.811366641,
     celldm(2)=1.004299035,
     celldm(3)=1.004242804,
     celldm(4)=-0.075786777,
     celldm(5)=-0.070940357,
     celldm(6)=-0.070881339,
     ecutwfc =40,
     ecutrho = 400,
     nat= 36,
     ntyp= 5,
     tot_charge=+1,
     occupations='smearing',
     !smearing='mp',
     degauss=0.03,
/
&electrons
     diagonalization='david',
     mixing_mode = 'plain',
     conv_thr =  1.0d-8,
     mixing_beta=0.3,
  /&end
ATOMIC_SPECIES
Cu 63.546   Cuh.pbe-dn-kjpaw_psl.0.2.UPF
O  15.999   O.pbe-n-kjpaw_psl.0.1.upf
Al 26.9815  Al.pbe-n-kjpaw_psl.0.1.upf
Si 28.0855  Si.pbe-n-kjpaw_psl.0.1.upf
P  30.9738  P.pbe-n-kjpaw_psl.0.1.upf
K_POINTS automatic
1 1 1  0 0 0
  ATOMIC_POSITIONS crystal
P        0.673048879   0.133060048   0.890018669....

------XSPECTRA input:

   &input_xspectra
      calculation='xanes_dipole',
      edge='K',
      verbosity='high',
      prefix='SAPO',
      xniter=5000,
      xcheck_conv=500,
      xepsilon(1)=1.0,
      xepsilon(2)=1.0,
      xepsilon(3)=1.0,
      xe0=-2.0102,
      xerror=0.01,
   /
   &plot
      xnepoint=1000,
      xgamma=1.5,
      xemin=-10.,
      xemax=80.0,
      terminator=.true.,
      cut_occ_states=.true.,
   /
   &pseudos
      filecore='cu.wfc',
   /
   &cut_occ
   /
   1 1 1  0 0 0