[Pw_forum] Meatl USPP and light impurity atom

[Darío Fdez-Pello Lois]

Hi Emine,

Thanks once again for your reply and explanations!

Related to what you said about doing a test of tranferability
(iswitch=2, and &TEST card), is it possible to increase the total
number of electrons in the &TEST card for the, say, bulk metal? In
such a way that the H may donate some charge to the metal.

Look at the following output except, the PP has 6 valence electrons
but on the 3th and last entry there are 7 and 6.25 respectively and
the results of the former are really poor:

     n l     nl             e AE (Ry)        e PS (Ry)    De AE-PS (Ry)
     3 2     5D   1( 4.00)       -0.38352       -0.38352     0.00000030
     1 0     6S   1( 1.50)       -0.46038       -0.46038     0.00000066
     2 1     6P   1( 0.50)       -0.12980       -0.12980     0.00000024
--
     n l     nl             e AE (Ry)        e PS (Ry)    De AE-PS (Ry)
     3 2     5D   1( 4.00)       -0.43350       -0.43449     0.00098780
     1 0     6S   1( 1.00)       -0.49664       -0.49674     0.00010364
     2 1     6P   1( 1.00)       -0.15552       -0.15526    -0.00026814
--
     n l     nl             e AE (Ry)        e PS (Ry)    De AE-PS (Ry)
     3 2     5D   1( 4.00)       -0.28879       -0.09801    -0.19077538
     1 0     6S   1( 1.00)       -0.35863       -0.16223    -0.19639633
     2 1     6P   1( 2.00)       -0.03712        0.00000    -0.03712055
--
     n l     nl             e AE (Ry)        e PS (Ry)    De AE-PS (Ry)
     3 2     5D   1( 4.00)       -0.32927       -0.32874    -0.00053748
     1 0     6S   1( 2.00)       -0.41988       -0.42005     0.00017716
     2 1     6P   1( 0.00)       -0.10005       -0.10040     0.00034334
--
     n l     nl             e AE (Ry)        e PS (Ry)    De AE-PS (Ry)
     3 2     5D   1( 6.00)       -0.17986       -0.17925    -0.00061351
     1 0     6S   1( 0.00)       -0.34699       -0.34462    -0.00237051
     2 1     6P   1( 0.00)       -0.07413       -0.07460     0.00047171
--
     n l     nl             e AE (Ry)        e PS (Ry)    De AE-PS (Ry)
     3 2     5D   1( 5.00)       -0.24381       -0.24447     0.00065454
     1 0     6S   1( 1.00)       -0.37816       -0.37720    -0.00096032
     2 1     6P   1( 0.00)       -0.08390       -0.08449     0.00059227
--
     n l     nl             e AE (Ry)        e PS (Ry)    De AE-PS (Ry)
     3 2     5D   1( 4.00)       -0.24011       -0.23973    -0.00037453
     1 0     6S   1( 2.00)       -0.33447       -0.33468     0.00020786
     2 1     6P   1( 0.25)       -0.03101       -0.03121     0.00020354

Could that be the problem?


 Ciao!

   Darío.

2012/10/15 Emine Kucukbenli <kucukben at sissa.it>:
>
> Hi Dario,
> First, i think it would be better if you send an input/output etc so that we
> understand that the problem is not due to something else.
> Second, band structure/dos/lattice parameter/bulk modulus are not really
> transferability tests, as they are all done on the same underlying
> electronic structure. With transferability it is usually meant that the
> pseudopotential gives acceptable results for a bunch of different electronic
> environment, such as metallic or covalent, like a Fe pp in bulk metal and in
> a metalloenzyme surrounded by atoms like O or S.. or in your case, H.
> A quick way of having an idea on this property might be testing the pseudo
> in the generation stage with several different occupancies in its orbitals.
> (iswitch=2, and &TEST card)
> ciao
>
> emine kucukbenli, postdoc @theos, epfl switzerland
>
>
>
> Quoting Darío Fdez-Pello Lois <pello.lois at gmail.com>:
>
>> Hi Emine,
>>
>> Thanks for your reply.
>>
>> Indeed it looks like it is not transferable but what strikes me is the
>> good results of the bands structure, DOS, lattice parameter and bulk
>> modulus i.e. is there any other item to test a PP that I am missing?
>>
>> Darío.
>>
>> 2012/10/14, Emine Kucukbenli <kucukben at sissa.it>:
>>>
>>> Hi Dario,
>>> so you are saying that the pseudopotential you have generated is not
>>> as transferable as you wish it to be..
>>> emine kucukbenli, postdoc @theos, epfl switzerland
>>>
>>> Quoting Darío Fdez-Pello Lois <pello.lois at gmail.com>:
>>>
>>>> Dear all,
>>>>
>>>> I've generated a metal USPP and the bands structure and DOS are very
>>>> similar to the ones calculated by an All Electron code. What is more,
>>>> both lattice parameter and Bulk Modulus are in excellent agreement
>>>> with experiments and the same happens to each and every calculation
>>>> that has been performed in which only the metal was involved.
>>>>
>>>> However, awful results are shown when adding a light impurity atom,
>>>> namely H. For H, I've tried all PPs provided at QE's site.
>>>>
>>>> Thanks in advance,
>>>>
>>>>   Darío.
>>>>
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>>>
>>>
>>>
>>>
>
>