[Pw_forum] occupations from input

[sreekar guddeti]

>>  is it necessary to generate a new Al+ pseudopotential with occupations
>>  card reading as
>>  nl  l   occ
>>  3S  0  2.00
>>  3P  1  0.00
>>  3D  2  0.00

>Not at all
>But keep in mind that a calculation for a charged system is a bit
>difficult to converge, especially with respect to the cell size.

Sir Paulatto,
Thank you very much for your invaluable help. I got to understand that it is
to do with transferability of pseudopotentials, but sir i would like to ask
one last question regarding this occupations issue.
Suppose i have a single Mn atom in a GaAs supercell. The hole(spin dw)
associated with  Mn sits in one of the Mn d states (as i inferred from spin
resolved local moments on Mn atom (~5up + ~1dw )). I want to delocalize the
hole by setting the d spindown occupations to ~zero.
is there a way to specify this as i dont know the band number of hole
apriorily

sincerely
-- 
Sreekar Guddeti
BTech + MTech
IIT Bombay
India
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[Pw_forum] occupations from input

[Paolo Giannozzi]

On Sep 16, 2009, at 8:14 , sreekar guddeti wrote:
>
> Suppose i have a single Mn atom in a GaAs supercell.
> The hole(spin dw) associated with  Mn sits in one of the
> Mn d states (...). I want to delocalize the hole by setting
> the d spindown occupations to ~zero.  is there a way to
> specify this

no

---
Paolo Giannozzi, Dept of Physics, University of Udine
via delle Scienze 208, 33100 Udine, Italy
Phone +39-0432-558216, fax +39-0432-558222

[Pw_forum] occupations from input

[Lorenzo Paulatto]

On Tue, September 15, 2009 04:13, sreekar guddeti wrote:
>  nelec=2,
>  OCCUPATIONS
>  2.0 0.0 0.0 0.0 0.0 0.0
>
>  is this correct?

Yes it is.

>  is it necessary to generate a new Al+ pseudopotential with occupations
>  card reading as
>  nl  l   occ
>  3S  0  2.00
>  3P  1  0.00
>  3D  2  0.00

Not at all.

But keep in mind that a calculation for a charged system is a bit
difficult to converge, especially with respect to the cell size.

best regards



-- 
Lorenzo Paulatto
SISSA  &  DEMOCRITOS (Trieste)
phone: +39 040 3787 511
skype: paulatz
www:   http://people.sissa.it/~paulatto/




  SISSA Webmail https://webmail.sissa.it/
  Powered by SquirrelMail http://www.squirrelmail.org/

[Pw_forum] occupations from input

[sreekar guddeti]

>Hi Srekar,
Hello Sir Paulatto,

>which example are you talking about?

in example 11 , scf calculation of  isolated neutral Al is performed.
suppose i want to do similar calculation for isolated Al+ ion, i gave input
parameters as

nelec=2,
OCCUPATIONS
2.0 0.0 0.0 0.0 0.0 0.0

is this correct?
is it necessary to generate a new Al+ pseudopotential with occupations card
reading as
nl  l   occ
3S  0  2.00
3P  1  0.00
3D  2  0.00

sincerely,
Sreekar Guddeti
BTech+MTech
E.Physics
IIT Bombay
India
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[Pw_forum] occupations from input

[sreekar guddeti]

Dear Sir Paulatto,
is it necessary to generate a new pseudopotential corresponding to the new
occupations because the example doesnt do so. it uses Al pseudopotential
corresponding to occupations
nl  l   occ
3S  0  2.00
3P  1  1.00
3D  2  0.00

whereas the occupations card reads
OCCUPATIONS
1.0 1.0 1.0 1.0 0.0 0.0
1.0 1/3 1/3 1/3

sincerely,
Sreekar Guddeti
BTech + MTech
Engineering Physics
IIT Bombay
India


> >  Can somebody clearly tell me how to define occupations from input. I
> cant
...

> It's quite easy, actually, there are only a couple of points you have to
> keep in mind:
>
> 1. if nspin=1 occupations can go from 0 to 2, you have to specify the
> occupation from the lower to the highest band and the sum of the
> occupations will have to be the number of electrons;
>
> 2. if nspin=2 occupations go from 0 to 1, you specify the occupation for
> spin up first, then for spin down (always on a newline);
>
> Let's say you want to reproduce the calculation of the Cr isolated atom,
> with semicore states in valence: 3s2 3p6 4s1 3d5 4p0
>
> first with nspin=1 and spherical (as it is done in ld1.x):
> OCCUPATIONS
>  22 2 2   1   1 1 1 1 1   0 0 0
> !3s23p6   4s1 3d54p0
>
> then spin polarized (nspin=2), according to Hund's rule you have to
> maximize the total angular momentum:
> OCCUPATIONS
>  11 1 1   1   1 1 1 1 1   0 0 0
>  11 1 1   0   0 0 0 0 0   0 0 0
> !3s23p6   4s1 3d54p0
>

-- 
Sreekar Guddeti
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[Pw_forum] occupations from input

[Lorenzo Paulatto]

In data 14 settembre 2009 alle ore 12:55:38, sreekar guddeti  
 ha scritto:
> is it necessary to generate a new pseudopotential corresponding to the  
> new occupations because the example doesnt do so.

Hi Srekar,
which example are you talking about?

> it uses Al pseudopotential
> corresponding to occupations
> nl  l   occ
> 3S  0  2.00
> 3P  1  1.00
> 3D  2  0.00

that's correct

>
> whereas the occupations card reads
> OCCUPATIONS
> 1.0 1.0 1.0 1.0 0.0 0.0
> 1.0 1/3 1/3 1/3

There is some error here: the upper line specify 6 occupations (6 spin-up  
bands) while the lower one only specifies 4 bands, but the number of  
spin-up and spin-down bands must be equal! Furthermore you have a total of  
6 electrons, which is twice as much as the Al atom.

If you don't specify nbnd you'll have 2 bands, and you'll have to specify  
2 occupations for spin-up and 2 for spin-down. If you have manually set  
nbnd to any other number (I would use at least 4), you'll have to specify  
that many occupations (of course the higher ones will be zero).

Best regards


-- 
Lorenzo Paulatto
SISSA  &  DEMOCRITOS (Trieste)
phone: +39 040 3787 511
skype: paulatz
www:   http://people.sissa.it/~paulatto/

 *** save italian brains ***
  http://saveitalianbrains.wordpress.com/

[Pw_forum] occupations from input

[udayagiri sai babu]

dear Lorenzo PaulattoThank you for you clear explanation i understood it
now. previously i was not clear how these fractions are coming but now it is
clear. Thank you very much for your explanation

On Sat, Sep 12, 2009 at 1:45 PM, Lorenzo Paulatto  wrote:

>
> On Sat, September 12, 2009 08:15, udayagiri sai babu wrote:
> >  Dear all
> >  Can somebody clearly tell me how to define occupations from input. I
> cant
> >  find much about that in this forum. The card "occupations" described in
> >  the
> >  example 11 for Al is not at all clear to me. What are those values mean.
> >  Looking forward to your help
>
>
> It's quite easy, actually, there are only a couple of points you have to
> keep in mind:
>
> 1. if nspin=1 occupations can go from 0 to 2, you have to specify the
> occupation from the lower to the highest band and the sum of the
> occupations will have to be the number of electrons;
>
> 2. if nspin=2 occupations go from 0 to 1, you specify the occupation for
> spin up first, then for spin down (always on a newline);
>
> Let's say you want to reproduce the calculation of the Cr isolated atom,
> with semicore states in valence: 3s2 3p6 4s1 3d5 4p0
>
> first with nspin=1 and spherical (as it is done in ld1.x):
> OCCUPATIONS
>  22 2 2   1   1 1 1 1 1   0 0 0
> !3s23p6   4s1 3d54p0
>
> then spin polarized (nspin=2), according to Hund's rule you have to
> maximize the total angular momentum:
> OCCUPATIONS
>  11 1 1   1   1 1 1 1 1   0 0 0
>  11 1 1   0   0 0 0 0 0   0 0 0
> !3s23p6   4s1 3d54p0
>
> Chrome is a lucky case, as it has a spherical ground state. As a last
> example let's take an oxygen atom (2s2 2p4) and set the occupations to
> reproduce the ld1.x calculation:
> OCCUPATIONS
>  2  4/3 4/3 4/3
>
> or, equivalently:
> OCCUPATIONS
>  21.33 1.33 1.34
>
>
> I hope it helps, best regards
>
> --
> Lorenzo Paulatto
> SISSA  &  DEMOCRITOS (Trieste)
> phone: +39 040 3787 511
> skype: paulatz
> www:   http://people.sissa.it/~paulatto/
>
>
>
> 
>  SISSA Webmail https://webmail.sissa.it/
>  Powered by SquirrelMail http://www.squirrelmail.org/
>
> ___
> Pw_forum mailing list
> Pw_forum at pwscf.org
> http://www.democritos.it/mailman/listinfo/pw_forum
>



-- 
U.Saibabu
PhD student,
Deformation mechanisms modeling group,
Materials engineering department,
IISc Bangalore,
India.
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[Pw_forum] occupations from input

[udayagiri sai babu]

Dear Xirainbow
If i have to write occupations from input for say for Cr (nbnd=12) how does
my occupations card look like


On Sat, Sep 12, 2009 at 11:59 AM, xirainbow  wrote:

> Dear udayagiri sai babu? *If you deal with non-metal, you can choose
> "fixed".*
> In metal, band structure will cross fermi level. This may result into
> non-convergence of scf calculation.
> *Therefore,if you deal with metal, the occupation can accelerate the
> convergence.*
> *But you much check the convergence of the occupation value.*
>
> http://blog.sina.com.cn/s/blog_5f15ead20100d1ki.html
> There are some convergence test result. I hope it will give you some help??
> *
> *
> On Sat, Sep 12, 2009 at 6:15 AM, udayagiri sai babu  gmail.com>wrote:
>
>> Dear all
>> Can somebody clearly tell me how to define occupations from input. I cant
>> find much about that in this forum. The card "occupations" described in the
>> example 11 for Al is not at all clear to me. What are those values mean.
>> Looking forward to your help
>>
>>
>> --
>> U.Saibabu
>> PhD student,
>> Deformation mechanisms modeling group,
>> Materials engineering department,
>> IISc Bangalore,
>> India.
>>
>>
>> ___
>> Pw_forum mailing list
>> Pw_forum at pwscf.org
>> http://www.democritos.it/mailman/listinfo/pw_forum
>>
>>
>
>
> --
> 
> Hui Wang
> School of physics, Nankai University, Tianjin, China
>
> ___
> Pw_forum mailing list
> Pw_forum at pwscf.org
> http://www.democritos.it/mailman/listinfo/pw_forum
>
>


-- 
U.Saibabu
PhD student,
Deformation mechanisms modeling group,
Materials engineering department,
IISc Bangalore,
India.
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[Pw_forum] occupations from input

[udayagiri sai babu]

Dear all
Can somebody clearly tell me how to define occupations from input. I cant
find much about that in this forum. The card "occupations" described in the
example 11 for Al is not at all clear to me. What are those values mean.
Looking forward to your help


-- 
U.Saibabu
PhD student,
Deformation mechanisms modeling group,
Materials engineering department,
IISc Bangalore,
India.
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[Pw_forum] occupations from input

[Lorenzo Paulatto]

On Sat, September 12, 2009 08:15, udayagiri sai babu wrote:
>  Dear all
>  Can somebody clearly tell me how to define occupations from input. I cant
>  find much about that in this forum. The card "occupations" described in
>  the
>  example 11 for Al is not at all clear to me. What are those values mean.
>  Looking forward to your help


It's quite easy, actually, there are only a couple of points you have to
keep in mind:

1. if nspin=1 occupations can go from 0 to 2, you have to specify the
occupation from the lower to the highest band and the sum of the
occupations will have to be the number of electrons;

2. if nspin=2 occupations go from 0 to 1, you specify the occupation for
spin up first, then for spin down (always on a newline);

Let's say you want to reproduce the calculation of the Cr isolated atom,
with semicore states in valence: 3s2 3p6 4s1 3d5 4p0

first with nspin=1 and spherical (as it is done in ld1.x):
OCCUPATIONS
  22 2 2   1   1 1 1 1 1   0 0 0
!3s23p6   4s1 3d54p0

then spin polarized (nspin=2), according to Hund's rule you have to
maximize the total angular momentum:
OCCUPATIONS
  11 1 1   1   1 1 1 1 1   0 0 0
  11 1 1   0   0 0 0 0 0   0 0 0
!3s23p6   4s1 3d54p0

Chrome is a lucky case, as it has a spherical ground state. As a last
example let's take an oxygen atom (2s2 2p4) and set the occupations to
reproduce the ld1.x calculation:
OCCUPATIONS
  2  4/3 4/3 4/3

or, equivalently:
OCCUPATIONS
  21.33 1.33 1.34


I hope it helps, best regards

-- 
Lorenzo Paulatto
SISSA  &  DEMOCRITOS (Trieste)
phone: +39 040 3787 511
skype: paulatz
www:   http://people.sissa.it/~paulatto/




  SISSA Webmail https://webmail.sissa.it/
  Powered by SquirrelMail http://www.squirrelmail.org/

[Pw_forum] occupations from input

[xirainbow]

Dear udayagiri sai babu?*Sorry, I am not fully understand what you want??*

*You can find how to set occupation at example directory.*
For example:

occupation = 'smearing'
smearing = 'gaussian'
degauss=0.001
/

Or you can use PWgui for convenience??

On Sat, Sep 12, 2009 at 6:52 AM, udayagiri sai babu wrote:

> Dear Xirainbow
> If i have to write occupations from input for say for Cr (nbnd=12) how does
> my occupations card look like
>


Hui Wang
School of physics, Nankai University, Tianjin, China
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[Pw_forum] occupations from input

[xirainbow]

Dear udayagiri sai babu? *If you deal with non-metal, you can choose
"fixed".*
In metal, band structure will cross fermi level. This may result into
non-convergence of scf calculation.
*Therefore,if you deal with metal, the occupation can accelerate the
convergence.*
*But you much check the convergence of the occupation value.*

http://blog.sina.com.cn/s/blog_5f15ead20100d1ki.html
There are some convergence test result. I hope it will give you some help??
*
*
On Sat, Sep 12, 2009 at 6:15 AM, udayagiri sai babu wrote:

> Dear all
> Can somebody clearly tell me how to define occupations from input. I cant
> find much about that in this forum. The card "occupations" described in the
> example 11 for Al is not at all clear to me. What are those values mean.
> Looking forward to your help
>
>
> --
> U.Saibabu
> PhD student,
> Deformation mechanisms modeling group,
> Materials engineering department,
> IISc Bangalore,
> India.
>
>
> ___
> Pw_forum mailing list
> Pw_forum at pwscf.org
> http://www.democritos.it/mailman/listinfo/pw_forum
>
>


-- 

Hui Wang
School of physics, Nankai University, Tianjin, China
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