[Pw_forum] The 'PAWPROJ' option in projwfc.x

[Ifeanyi John ONUORAH]

Thank you.

2016-04-28 17:35 GMT+02:00 Holzwarth, Natalie <natalie at wfu.edu>:

> Dear  Ifeanyi J.,
>       I am not sure if the individual terms are very meaningful.    They
> should depend on the shapes of the basis and projector functions that were
> generated for the particular UPF dataset that you are using.    The sum of
> them however should be more robust.   Note that the sum approximates the
> charge in a sphere around the H that has the radius of the so-called
> augmentation sphere about the atom.
>
> Sincerely, Natalie Holzwarth
>
> N. A. W. Holzwarth                                       email:
> natalie at wfu.edu
> Department of Physics                                  web:
> http://www.wfu.edu/~natalie
> Wake Forest University                                 phone:
> 1-336-758-5510
> Winston-Salem, NC 27109 USA                     office: Rm. 300 Olin
> Physical Lab
>
> On Thu, Apr 28, 2016 at 10:08 AM, Ifeanyi John ONUORAH <
> ifeanyijohn.onuorah at studenti.unipr.it> wrote:
>
>> Dear Holzwarth,
>> Thank you for the note it has already helped a lot. Using the pawproj and
>> adding the two contributions give very good results when compared with
>> experimental results for my calculations. I am still trying to understand
>> while one of the contributions is always positive and the other negative.
>> If it depends on the assigned occupation of each of the two projector and
>> basis function for the H s channel?
>>
>> Thank you
>>
>> Onuorah Ifeanyi J.
>> PhD student,
>> Department of Physics and Earth Sciences,
>> University of Parma,
>> Italy.
>>
>> 2016-04-28 15:33 GMT+02:00 Holzwarth, Natalie <natalie at wfu.edu>:
>>
>>> Dear Ifeanyi J.,
>>>         The pawproj=.true. option calculates the overlap of each PAW
>>> projector function with the pseudo wavefunction in order to estimate the
>>> charge within the augmentation radius associated with each atom.    If you
>>> have two projector and basis functions for H in the s channel, they would
>>> both contribute.     By summing the two contributions you can approximate
>>> the charge within the augmentation radius.    In principle, if your
>>> projector and basis set "spans" the function space, you would get a good
>>> estimate of the charge.    See attached notes if interested in more
>>> details.   Without  pawproj=.true., the program calculates the partial
>>> densities of states using a weight factor for an atomic pseudofunction
>>> stored in the UPF file.    The results would be quantitatively different,
>>> but (hopefully) qualitatively similar.
>>>
>>> Sincerely, Natalie Holzwarth
>>>
>>> N. A. W. Holzwarth                                       email:
>>> natalie at wfu.edu
>>> Department of Physics                                  web:
>>> http://www.wfu.edu/~natalie
>>> Wake Forest University                                 phone:
>>> 1-336-758-5510
>>> Winston-Salem, NC 27109 USA                     office: Rm. 300 Olin
>>> Physical Lab
>>>
>>> On Thu, Apr 28, 2016 at 9:02 AM, Ifeanyi John ONUORAH <
>>> ifeanyijohn.onuorah at studenti.unipr.it> wrote:
>>>
>>>> Dear all,
>>>>
>>>> Using the projectors and all-electron PAW basis set to calculate weight
>>>> factors for the PDOS,LDOS by setting the pawproj option == .true., say for
>>>> hydrogen impurities in transition metals, give two contributions to the
>>>> hydrogen s orbital with files in the form '...(H)_wfc#1(s)' and
>>>> '...(H)_wfc#1(s)' i.e with wavefunction number 1 and 2. While without the
>>>> pawproj option only one file for the hydrogen atom is given in the form
>>>> '...(H)_wfc#1(s)'.
>>>>
>>>> I will appreciate if someone explains where these two contributions
>>>> with the 'pawproj' are coming from. I tried to look at the pseudopotential
>>>> file but it is not clear still,  I used this  H.pbe-kjpaw_psl.0.1.UPF on
>>>> the quantum espresso webpage and QE version  5.3.0. Also, I will like to
>>>> point that doing the integration of the difference of the ldos(up and down)
>>>> till the fermi energy results with one file giving a negative contribution,
>>>> while the other positive.
>>>>
>>>>
>>>> Onuorah Ifeanyi J.
>>>> PhD student,
>>>> Department of Physics and Earth Sciences,
>>>> University of Parma,
>>>> Italy.
>>>>
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>>>>
>>>
>>>
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>>
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