[Pw_forum] Problem with PDOS of ionic crystals

[Alexander G. Kvashnin]

Dear Giovanni,

Thank you for your quick answer!
As I understand correctly, I am not able to calculate correct PDOS while I
have no d orbitals in the pseudo?

 *--*

*Sincerely yours,*
*Alexander G. Kvashnin *


*=====================================================PhD Student Moscow
Institute of Physics and Technology          http://mipt.ru/
<http://s.wisestamp.com/links?url=http%3A%2F%2Fmipt.ru%2F&sn=>*
*141700, Institutsky lane 9, Dolgoprudny, Moscow Region, Russia*





*Junior research scientistTechnological Institute for Superhard and Novel
Carbon Materials                                http://www.tisnum.ru/
<http://s.wisestamp.com/links?url=http%3A%2F%2Fwww.tisnum.ru%2F&sn=>
<http://s.wisestamp.com/links?url=http%3A%2F%2Fwww.ntcstm.troitsk.ru%2F&sn=>142190,
Central'naya St. 7a, Troitsk, Moscow Region,
Russia=====================================================*


On 4 April 2014 13:18, Giovanni Cantele <giovanni.cantele at spin.cnr.it>wrote:

>
> On 04 Apr 2014, at 10:43, Alexander G. Kvashnin <agkvashnin at gmail.com>
> wrote:
>
> Dear QE users,
>
> I tried to calculate PDOS for simple cubic NaCl structure. I performed an
> optimization vc-relax with 6x6x6 k-points, than I made scf calculations,
> nscf calculations and after that I ran projwfc to plot PDOS.
> My question is why when I plotted DOS_Na+DOS_Cl it differs from the total
> DOS for whole system, specially in conduction band?
>
> Here is my nscf file and input file for projfwc:
>
>  &control
>     calculation='nscf'
>     restart_mode='restart',
>     tstress = .true.
>     tprnfor = .true.
>     prefix='nacl',
>     pseudo_dir = '.',
>     outdir='.',
>     nstep = 200
>  /
>  &system
>                     nosym = .false.,
>                      ibrav = 1,
>                      nat = 4,
>                      ntyp = 2,
>                      ecutwfc = 30,
>                      celldm(1) = 10.750047341391399,
>                      occupations = 'tetrahedra',
>  /
>  &electrons
>     conv_thr =  1.0d-8
>     mixing_beta = 0.7
>     electron_maxstep = 300
>  /
> ATOMIC_SPECIES
>  Na    22.9897    Na.pbe-sp-van_ak.UPF
>  Cl    35.4527    Cl.pbe-n-van.UPF
> ATOMIC_POSITIONS  crystal
> Na      -0.500000000  -0.500000000   0.000000000
> Na      -0.500000000   0.000000000  -0.500000000
> Cl      -0.500000000   0.000000000   0.000000000
> Cl      -0.500000000  -0.500000000  -0.500000000
> Cl       0.000000000  -0.500000000   0.000000000
> Cl       0.000000000   0.000000000  -0.500000000
> Na       0.000000000   0.000000000   0.000000000
> Na       0.000000000  -0.500000000  -0.500000000
> K_POINTS automatic
>  6 6 6  0 0 0
>
>  &inputpp
>     outdir='./'
>     prefix='nacl'
>     ngauss=1, degauss=0.02
>     DeltaE=0.05
>     Emin=-15.0, Emax=15.0,
>     filpdos='nacl.k'
>  /
>
>
> Any suggestion are welcome!
> Thank you in advance!
>  *--*
> *Sincerely yours,*
> *Alexander G. Kvashnin *
>
>
> *=====================================================PhD Student Moscow
> Institute of Physics and Technology          http://mipt.ru/
> <http://s.wisestamp.com/links?url=http%3A%2F%2Fmipt.ru%2F&sn=>*
> *141700, Institutsky lane 9, Dolgoprudny, Moscow Region, Russia*
>
>
>
>
>
> *Junior research scientistTechnological Institute for Superhard and Novel
> Carbon Materials                                http://www.tisnum.ru/
> <http://s.wisestamp.com/links?url=http%3A%2F%2Fwww.tisnum.ru%2F&sn=>
> <http://s.wisestamp.com/links?url=http%3A%2F%2Fwww.ntcstm.troitsk.ru%2F&sn=>142190,
> Central'naya St. 7a, Troitsk, Moscow Region,
> Russia=====================================================*
>
>
>
>
> Dear Alexander,
>
> inside the pdos output file you should find, for EACH eigenvalue at EACH
> k-point the decomposition of
> the wave function, together with the sum of the square modulus of the
> expansion coefficients.
>
> What you should notice is that, while for occupied states |psi|^2 = 1.000,
> the coefficient square moduli do
> not sum up to 1, as you move to high energy unoccupied states.
>
> Should the basis set used for the projection be orthogonal and complete,
> that should not occur. However,
> the code, as far as I remember, is only able to project onto the atomic
> orbitals included in the pseudo potentials.
>
> Therefore, while the bands, even though unoccupied, are correctly (at DFT
> level!) computed, the projection onto
> the atomic orbitals might not be enough because would require atomic
> orbitals (e.g. d states) not included
> in the pseudo. The result is that the sum of the partial dos is LESS than
> the (correct) total DOS.
>
> Giovanni
>
> --
>
> Giovanni Cantele, PhD
> CNR-SPIN
> c/o Dipartimento di Fisica
> Universita' di Napoli "Federico II"
> Complesso Universitario M. S. Angelo - Ed. 6
> Via Cintia, I-80126, Napoli, Italy
> e-mail: giovanni.cantele at spin.cnr.it
> Phone: +39 081 676910
> Skype contact: giocan74
>
> ResearcherID: http://www.researcherid.com/rid/A-1951-2009
> Web page: http://people.na.infn.it/~cantele
>
>
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