----- Reply message -----
From: "Ary Junior" <[email protected]>
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
?/

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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