[Pw_forum] Mo pseudopotential

Andrea Dal Corso dalcorso at sissa.it
Fri Mar 29 16:38:49 CET 2013


On Tue, 2013-03-26 at 17:54 -0700, mgtmentink at lbl.gov wrote:
> 
> 
> ----- Reply message -----
> From: "Ary Junior" <aryjunior at gmail.com>
> To: "PWSCF Forum" <pw_forum at pwscf.org>
> Subject: [Pw_forum] Mo pseudopotential
> Date: Tue, Mar 26, 2013 2:38 pm
> 
> 
> 
> Dear all,
> 
> I was looking for a PBE USPP for molybdenum and checked that the .UPF
> files available in the QE website are the ones provided in pslibrary
> 0.2... So, based in the input file I created a test for the
> Mo.pbe-spn-rrkjus_psl.0.2.UPF file like this:
> 
>  &input
>    title='Mo',
>    zed=42.0,
>    rel=1,
>    config='[Kr] 4d5.0 5s1 5p0',
>    iswitch=2,
>    dft='PBE',
>    rlderiv=2.93, eminld=-3.0, emaxld=3.0, deld=0.01, nld=3
>  /
>  &test
>    file_pseudo='Mo.pbe-spn-rrkjus_psl.0.2.UPF',
>    nconf=1, 
>    configts(1)='4d5.0 5s1 5p0',
>    ecutmin=50, ecutmax=200, decut=50
>  /
> 

The Mo of the pslibrary has 4s and 4p semicore states in the valence, so
you have to include them in the test configuration. With something like:

configts(1)='4s2.0 4p6.0 4d5.0 5s1 5p0'

the pp seems to work.

HTH,

Andrea

> Besides some warnings after the "All-electron run" section, the
> difference between the AE and the PS eigenvalues are zero and it is
> ok...
> 
>      n l     nl             e AE (Ry)        e PS (Ry)    De AE-PS
> (Ry)
>      3 2     4D   1( 5.00)       -0.27582       -0.27582
> 0.00000
>      1 0     5S   1( 1.00)       -0.30033       -0.30033
> 0.00000
>      2 1     5P   1( 0.00)       -0.07669       -0.07669
> 0.00000
> 
> However, when compare these eigenvalues with an atomic calculation
> using the spherical Bessel functions I got a weird result, even with a
> high cutoff energy:
> 
>      Cutoff (Ry) :  200.0
>                            N = 1       N = 2       N = 3
>      E(L=0) =       -23.1157 Ry  -13.3019 Ry   -9.0812 Ry
>      E(L=1) =       -20.7569 Ry  -11.9179 Ry   -7.7609 Ry
>      E(L=2) =       -17.0812 Ry   -9.9089 Ry   -6.4930 Ry
> 
> Moreover, the AE vs PS logarithmic derivatives are quite discrepant,
> even at lower r values... The point is that after analyzing the shape
> of the AE orbitals I couldn't understand the so low rcut values in the
> pslibrary input file in both versions, 0.2 and 0.3... I have done the
> same test for other PBE USPPs available in the QE website like
> Ni.pbe-n-rrkjus_psl.0.1.UPF, O.pbe-n-rrkjus_psl.0.1.UPF and
> S.pbe-n-rrkjus_psl.0.1.UPF and they are fine... So, I tried to reset
> the input file with radii more compatible with the AE wavefunctions in
> my conception, besides change the core corrections like this:
> 
>  &input
>    title='Mo',
>    prefix='Mo',
>    zed=42.0,
>    config='[Kr] 5s1 4d5 5p0',
>    iswitch=3,
>    dft='PBE',
>    rlderiv=2.93, eminld=-3.0, emaxld=3.0, deld=0.01, nld=3,
>  /
>  &inputp
>    pseudotype=3,
>    file_pseudopw='Mo.PBE-spn-rrkjus_aryjr.UPF',
>    author='ADC',
>    lloc=-1,
>    rcloc=3.2,
>    which_augfun='PSQ',
>    rmatch_augfun=1.3,
>    nlcc=.true.,
>    new_core_ps=.true.,
>    rcore=1.0,
>    tm=.true.
>  /
> 6
> 5S  1  0  1.00  0.00  2.70  3.30  0.0
> 5S  1  0  0.00  7.00  2.50  3.30  0.0
> 5P  2  1  0.00  0.00  3.20  3.30  0.0
> 5P  2  1  0.00  7.00  3.20  3.30  0.0
> 4D  3  2  5.00  0.00  1.50  1.70  0.0
> 4D  3  2  0.00 -0.30  0.70  1.70  0.0
> 
> Then, I think that everything is fine with the AE and the PS
> eigenvalues:
> 
>      n l     nl             e AE (Ry)        e PS (Ry)    De AE-PS
> (Ry)
>      1 0     5S   1( 1.00)       -0.30033       -0.30033
> 0.00000
>      3 2     4D   1( 5.00)       -0.27582       -0.27582
> 0.00000
>      2 1     5P   1( 0.00)       -0.07669       -0.07669
> -0.00000
> 
> And after compare these eigenvalues with an atomic calculation using
> the spherical Bessel functions again, things look better now:
> 
>      Cutoff (Ry) :   50.0
>                            N = 1       N = 2       N = 3
>      E(L=0) =        -0.3002 Ry   -0.0021 Ry    0.0380 Ry
>      E(L=1) =        -0.0766 Ry    0.0213 Ry    0.0681 Ry
>      E(L=2) =        -0.2681 Ry    0.0313 Ry    0.0692 Ry
> 
>      Cutoff (Ry) :  200.0
>                            N = 1       N = 2       N = 3
>      E(L=0) =        -0.3002 Ry   -0.0021 Ry    0.0380 Ry
>      E(L=1) =        -0.0766 Ry    0.0213 Ry    0.0681 Ry
>      E(L=2) =        -0.2683 Ry    0.0313 Ry    0.0692 Ry
> 
> The AE vs PS logarithmic derivatives are being well reproduced in
> energies lower than 1 Ry.... I also tested chemical states like the
> ionized Mo4+ and Mo6+, and the results are listed below:
> 
>      1 0     5S   1( 1.00)       -0.30033       -0.30033
> 0.00000
>      3 2     4D   1( 5.00)       -0.27582       -0.27582
> 0.00000
>      2 1     5P   1( 0.00)       -0.07669       -0.07669
> -0.00000
>      Etot =   -8097.243530 Ry,   -4048.621765 Ha, -110168.600949 eV
>      Etotps =   -32.753518 Ry,     -16.376759 Ha,    -445.634282 eV
> 
>      1 0     5S   1( 0.00)       -2.69065       -2.78173
> 0.09108
>      3 2     4D   1( 2.00)       -3.40343       -3.51010
> 0.10667
>      2 1     5P   1( 0.00)       -2.17762       -2.27343
> 0.09581
>      dEtot_ae =       6.511981 Ry
>      dEtot_ps =       6.625031 Ry,   Delta E=      -0.113050 Ry
> 
>      1 0     5S   1( 0.00)       -4.30796       -4.58873
> 0.28077
>      3 2     4D   1( 0.00)       -5.60739       -5.87530
> 0.26791
>      2 1     5P   1( 0.00)       -3.66423       -3.99180
> 0.32756
>      dEtot_ae =      15.474602 Ry
>      dEtot_ps =      15.954369 Ry,   Delta E=      -0.479767 Ry
> 
> My question: is my procedure described above wrong? Study and
> understand the generation of PSPs is not easy for me and I'm trying to
> learn it grounded in some textbooks as well as some documents spread
> on the internet and of course the input files provided in the
> pslibrary project. But this PBE USPP for molybdenum made me a little
> bit confused. I tested both in a MoS2 unit cell with PBE-D and the
> cell volume as well as the interatomic distances are fine if compared
> with the experiments, with differences lower than 3%... One more
> question: how can I improve the result for the Mo4+ and Mo6+ ionized
> states?
> 
> Thank you very much!
> 
> Ary Junior
> 
> Doctoral Student
> Chemistry Department
> Universidade Federal de Juiz de Fora - MG - Brasil
> 
> -- 
> http://lattes.cnpq.br/8221674673413336 
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-- 
Andrea Dal Corso                    Tel. 0039-040-3787428
SISSA, Via Bonomea 265              Fax. 0039-040-3787249
I-34136 Trieste (Italy)             e-mail: dalcorso at sissa.it





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