[Pw_forum] Pseudo-potential testing

[Tram Bui]

Dear Gabriele,
    Thank you for your respond. Just to make sure that I'm understanding
your answer correctly, below is a shortcut on the output file of my PP
testing:

---------------------- Testing the pseudopotential ----------------------


     scalar relativistic calculation

     atomic number is 55.00   valence charge is  1.00
     dft =PBE   lsd =0 sic =0 latt =0  beta=0.20 tr2=1.0E-14
     mesh =1251 r(mesh) = 101.25750 xmin = -7.00 dx = 0.01250

     n l     nl             e AE (Ry)        e PS (Ry)    De AE-PS (Ry)
     1 0     6S   1( 0.50)       -0.17728       -0.17238       -0.00490
     2 1     6P   1( 0.50)       -0.07657       -0.07687        0.00030
     3 2     5D   1( 0.00)       -0.05580       -0.05081       -0.00499

     eps = 8.5E-15  iter = 22

     Etot =  -15573.817276 Ry,   -7786.908638 Ha, -211892.560039 eV
     Etotps =    -0.217507 Ry,      -0.108753 Ha,      -2.959329 eV
     dEtot_ae =       0.049938 Ry
     dEtot_ps =       0.048795 Ry,   Delta E=       0.001144 Ry

     Ekin =       0.080184 Ry,       0.040092 Ha,       1.090963 eV
So I should look at the "De AE-PS (Ry)", which is the difference in the
eigenvalues? or the "Delta E"? I assume it is the Delta E based on your
respond. But am I correct?

Regards,
Tram

On Thu, May 26, 2011 at 2:16 AM, Gabriele Sclauzero <sclauzer at sissa.it>wrote:

>
> Il giorno 26/mag/2011, alle ore 01.00, Tram Bui ha scritto:
>
> Dear Paul,
>        In the file that I have attached here (Paul's note on PP
> generation), under section 3.10: checking for transferability, you have
> mentioned about the:"The error on total energy differences
> between PP and AE results gives a feeling on how good the PP is." Do you
> mean the difference in AE and PP eigenvalues?
>
>
> No, I think here Paolo "Paul" Giannozzi really meant what you understood
> first, but you didn't get it in the correct way.
> You should really compare total energy differences, which means:
> E_2(AE) - E_1(AE)    versus   E_2(PS) - E_1(PS)
> where 1 and 2 label two different electronic configurations, and NOT
> E_1(PS)  versus  E_1(AE)
> as you are probably trying to do.
>
> because I saw the Etot and Etotps are huge difference
>
>
> This is often the case, given the high degree of freedom in the choice of
> PP parameters (especially for the local potential, I suppose).
>
> but their eigenvalue (e, Ry) are closed.
>
>
> Indeed this is how it should be, since the modern PP are designed to
> reproduce the scattering properties of the AE atomic potential as best as
> possible.
>
>
> Dear QE users,
>      I'm trying to test the Cs' US PP with reference configuration of :[Xe]
> 6s1 5d0 6p0. To test the PP, I'm using these five configuration (just by
> guessing):
>      configts(1)= '6s1 6p0 5d0'
>      configts(2)= '6s0.5 6p0.5 5d0'
>      configts(3)= '6s0.5 6p0 5d0.5'
>      configts(4)= '6s0 6p1 5d0'
>      configts(5)= '6s0 6p0 5d1'
> My questions are:
>  - how to choose the configurations for PP testing based on the reference
> one? is there a strategy or some sort?
>
>
> Use some reasonable configurations (remove or add one electron, or a
> fraction of it, move one or more electrons between different orbitals, ...).
> The choice may also be driven by the class of materials that you are going
> to study (e.g. ionic crystals).
>
>  - how many configurations are enough for the test?
>
>
> That's up to you... 5 look enough for me. Don't forget to do some testing
> with the solid state code (e.g. bond distance of dimers, lattice constant of
> simple solids...).
>
>
> HTH
>
>
> GS
>
>
> Thank you very much,
>
> Tram Bui
>
> M.S. Materials Science & Engineering
> trambui at u.boisestate.edu
>
> <pseudo-gen.pdf>_______________________________________________
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>
>
>
> § Gabriele Sclauzero, EPFL SB ITP CSEA
> *   PH H2 462, Station 3, CH-1015 Lausanne*
>
>
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>


-- 
Tram Bui

M.S. Materials Science & Engineering
trambui at u.boisestate.edu
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