[Wien] Interstitial N-N pair in GaP supercell

[Peter Blaha]

It is of course a normal behaviour for sturcture mininization.

You run a scf cycle; after 18 cycles it is converged, and the program 
finds the forces on the atoms. Using the forces, the program mini will 
move the atoms and the next scf cycle will start. Usually, this should 
produce smaller forces now, and this procedure continues many times until 
the forces are below a default value. Only then the minimization stops.

So what are your forces and what are the corresponding positions ?
Does it go into the expected direction ?
Is the total energy decreasing ?
You find all this in case.scf_mini.
But you really should read the UG to understand how min_lapw works.

Eventually your structure initialization was wrong.
Rerunx symmetry.   Are there any messages in case.outputs ??



> As I wrote in my previous letters, I am trying to minimize the atom
> positions in GaP supercell where one of the P atoms is replaced by N-N
> interstitial molecule.
> I found some strange (in my opinion) behaviour of  "mini".
> Apparently the convergence was achieved after 18 scf cycles with the
> output "ec cc and fc_conv 1 1 1". The  distance  between  relaxed  N-N
> atoms was 1.57 A.
> But the program did not stop and began to recalculate again from cycle 1.
> After 16 scf cycles the situation was repeated but now  the  distance 
> between  relaxed  N atoms was reduced down to  1.27 A.
> And so on without ending.
> In my opinion even 1.27 A  is already too small value (this is almost
> the interatomic distance in isolated N2 molecule), but it was
> decreasing  further and further.
> So, finally I had the problems with overlapping spheres in spite of very
> small  RMT(N)=1.1 bohr.
> 
> In output file of our cluster I found the following (below some fragment
> of this file is shown):
> 
> ..
> ..
> in cycle 18ETEST: .00011179   CTEST: -.0009873
> ec cc and fc_conv 1 1 1
> 
> >   stop
> Fallback to compatibility mode with "old" save_lapw
> broyden files deleted, clm*, dmat*, vorb*, vresp*, eece*, scf and struct
> files saved under GaPNN_1
> 20.841u 0.352s 0:21.70 97.6%0+0k 0+20648io 0pf+0w
> 0.844u 0.276s 0:01.54 72.0%0+0k 1272+16896io 8pf+0w
> clmextrapol_lapw has generated a new GaPNN.clmsum
> ec cc and fc_conv 0 0 0
> in cycle 2ETEST: 0   CTEST: 0
> ec cc and fc_conv 0 0 0
> in cycle 3ETEST: 0   CTEST: 0
> ec cc and fc_conv 0 0 0
> .
> .
> 
> 
> In my opinion 1.57 A  is much reasonable value for relaxed N-N distance
> then 1.27 A or even smaller value.
> I still wonder why the program begins recalculation after the apparently
> successful message: "ec cc and fc_conv 1 1 1"?
> 
> Is there some possibility that the reason is the specific position of
> N-N interstitial pair?  In my initial structure file  P(0,0,0) atom was
> replaced by N-N interstitial pair having the positions symmetrically
> shifted from (0,0,0) along  the z-direction. The constrains (0.0, 0.0,
> 1.0) in my case.inM   file  allow the displacement of N atoms only along
> the z-direction. My native thought was that may be (0,0,0) is some
> specific position in the supercell. If I know correctly, in usual
> minimization tasks with substitution impurity, the atom at (0,0,0)
> position should have full constrains in all directions. I tried to
> replace  other P atom in the middle of initial 2x2x2 supercell, but "x
> sgroup" always returns the converted supercell where N-N pair is near
> (0,0,0), (0.5,0.5,0.5), (0,0,0.5)  and so on   positions.
> 
> 
> I will be extremely thankful for any suggestion.
> Kakha
> 
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> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
> 


  P.Blaha
--
Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
Phone: +43-1-58801-15671 FAX: +43-1-58801-15698
Email: blaha at theochem.tuwien.ac.atWWW: http://info.tuwien.ac.at/theochem/
--

[Wien] Interstitial N-N pair in GaP supercell

[Kakhaber Jandieri]

Dear Wien2K users,

As I wrote in my previous letters, I am trying to minimize the atom
positions in GaP supercell where one of the P atoms is replaced by N-N
interstitial molecule.
I found some strange (in my opinion) behaviour of  "mini".
Apparently the convergence was achieved after 18 scf cycles with the
output "ec cc and fc_conv 1 1 1". The  distance  between  relaxed  N-N
atoms was 1.57 A.
But the program did not stop and began to recalculate again from cycle 1.
After 16 scf cycles the situation was repeated but now  the  distance 
between  relaxed  N atoms was reduced down to  1.27 A.
And so on without ending.
In my opinion even 1.27 A  is already too small value (this is almost
the interatomic distance in isolated N2 molecule), but it was
decreasing  further and further.
So, finally I had the problems with overlapping spheres in spite of very
small  RMT(N)=1.1 bohr.

In output file of our cluster I found the following (below some fragment
of this file is shown):

..
..
in cycle 18ETEST: .00011179   CTEST: -.0009873
ec cc and fc_conv 1 1 1

>   stop
Fallback to compatibility mode with "old" save_lapw
broyden files deleted, clm*, dmat*, vorb*, vresp*, eece*, scf and struct
files saved under GaPNN_1
20.841u 0.352s 0:21.70 97.6%0+0k 0+20648io 0pf+0w
0.844u 0.276s 0:01.54 72.0%0+0k 1272+16896io 8pf+0w
clmextrapol_lapw has generated a new GaPNN.clmsum
ec cc and fc_conv 0 0 0
in cycle 2ETEST: 0   CTEST: 0
ec cc and fc_conv 0 0 0
in cycle 3ETEST: 0   CTEST: 0
ec cc and fc_conv 0 0 0
.
.


In my opinion 1.57 A  is much reasonable value for relaxed N-N distance
then 1.27 A or even smaller value.
I still wonder why the program begins recalculation after the apparently
successful message: "ec cc and fc_conv 1 1 1"?

Is there some possibility that the reason is the specific position of
N-N interstitial pair?  In my initial structure file  P(0,0,0) atom was
replaced by N-N interstitial pair having the positions symmetrically
shifted from (0,0,0) along  the z-direction. The constrains (0.0, 0.0,
1.0) in my case.inM   file  allow the displacement of N atoms only along
the z-direction. My native thought was that may be (0,0,0) is some
specific position in the supercell. If I know correctly, in usual
minimization tasks with substitution impurity, the atom at (0,0,0)
position should have full constrains in all directions. I tried to
replace  other P atom in the middle of initial 2x2x2 supercell, but "x
sgroup" always returns the converted supercell where N-N pair is near
(0,0,0), (0.5,0.5,0.5), (0,0,0.5)  and so on   positions.


I will be extremely thankful for any suggestion.
Kakha

[Wien] Interstitial N-N pair in GaP supercell

[E.A.Moore]

I don't know why it starts again, but I guess there will be a minimum with the 
two atoms at the N2 distance as the N2 bond is very strong. You could start by 
putting your N atoms farther apart.

Elaine

-Original Message-
From: Kakhaber Jandieri [mailto:kakhaber.jandi...@physik.uni-marburg.de] 
Sent: 09 July 2010 15:33
To: A Mailing list for WIEN2k users
Subject: Re: [Wien] Interstitial N-N pair in GaP supercell

Dear Wien2K users,

As I wrote in my previous letters, I am trying to minimize the atom
positions in GaP supercell where one of the P atoms is replaced by N-N
interstitial molecule.
I found some strange (in my opinion) behaviour of  "mini".
Apparently the convergence was achieved after 18 scf cycles with the
output "ec cc and fc_conv 1 1 1". The  distance  between  relaxed  N-N
atoms was 1.57 A.
But the program did not stop and began to recalculate again from cycle 1.
After 16 scf cycles the situation was repeated but now  the  distance 
between  relaxed  N atoms was reduced down to  1.27 A.
And so on without ending.
In my opinion even 1.27 A  is already too small value (this is almost
the interatomic distance in isolated N2 molecule), but it was
decreasing  further and further.
So, finally I had the problems with overlapping spheres in spite of very
small  RMT(N)=1.1 bohr.

In output file of our cluster I found the following (below some fragment
of this file is shown):

..
..
in cycle 18ETEST: .00011179   CTEST: -.0009873
ec cc and fc_conv 1 1 1

>   stop
Fallback to compatibility mode with "old" save_lapw
broyden files deleted, clm*, dmat*, vorb*, vresp*, eece*, scf and struct
files saved under GaPNN_1
20.841u 0.352s 0:21.70 97.6%0+0k 0+20648io 0pf+0w
0.844u 0.276s 0:01.54 72.0%0+0k 1272+16896io 8pf+0w
clmextrapol_lapw has generated a new GaPNN.clmsum
ec cc and fc_conv 0 0 0
in cycle 2ETEST: 0   CTEST: 0
ec cc and fc_conv 0 0 0
in cycle 3ETEST: 0   CTEST: 0
ec cc and fc_conv 0 0 0
.
.


In my opinion 1.57 A  is much reasonable value for relaxed N-N distance
then 1.27 A or even smaller value.
I still wonder why the program begins recalculation after the apparently
successful message: "ec cc and fc_conv 1 1 1"?

Is there some possibility that the reason is the specific position of
N-N interstitial pair?  In my initial structure file  P(0,0,0) atom was
replaced by N-N interstitial pair having the positions symmetrically
shifted from (0,0,0) along  the z-direction. The constrains (0.0, 0.0,
1.0) in my case.inM   file  allow the displacement of N atoms only along
the z-direction. My native thought was that may be (0,0,0) is some
specific position in the supercell. If I know correctly, in usual
minimization tasks with substitution impurity, the atom at (0,0,0)
position should have full constrains in all directions. I tried to
replace  other P atom in the middle of initial 2x2x2 supercell, but "x
sgroup" always returns the converted supercell where N-N pair is near
(0,0,0), (0.5,0.5,0.5), (0,0,0.5)  and so on   positions.


I will be extremely thankful for any suggestion.
Kakha

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The Open University is incorporated by Royal Charter (RC 000391), an exempt 
charity in England & Wales and a charity registered in Scotland (SC 038302).

[Wien] Interstitial N-N pair in GaP supercell

[Kakhaber Jandieri]

Dear Elaine,

"I would have thought the local atom displacements would be more
important than the change in lattice constants. I assume your supercell
is chosen so that there is little or no N2-N2 interaction"

Yes, I consider dilute nitrides.

"The manual does advise as large an RMT as you can manage but if your N atoms 
are 1.4 apart and the RMT of N is 1.1, will not the cores overlap? The bond 
distance in the free molecule is 1.1. You may need to use an even smaller RMT. 
Of course very small RMTs do pose problems".

my RMT(N)=1.1 bohr = 1.1*0.53 = 0.583 A.
So 1.4 A > 2*RMT(N)= 1.166 A.

Thank you very much for reply.
Best wishes,
Kakha


E.A.Moore wrote:
> -Original Message-
> From: Kakhaber Jandieri [mailto:Kakhaber.Jandieri at physik.uni-marburg.de] 
> Sent: 06 July 2010 15:28
> To: A Mailing list for WIEN2k users
> Subject: Re: [Wien] Interstitial N-N pair in GaP supercell
>
>
>   
>> My final goal is to study the influence of these interstitial structures
>> on the structural factor.
>> Of course, the lattice parameters will be changed and it will have the
>> influence on the structural factor along with influence of atom
>> displacements.
>> 
>
> I would have thought the local atom displacements would be more important 
> than the change in lattice constants. I assume your supercell is chosen so 
> that there is little or no N2-N2 interaction.
>
>   
>> But, as far as I know,  the determination of lattice parameters is more
>> time-consuming task.
>> So on preliminary stage I decided to try the supercell with unchanged
>> lattice constants but with relaxed atom positions.
>> It was just interesting for me to see what happens.
>> Depending on the results, I will try to determine the lattice constants
>> and then relax the supercell.
>> Anyway, I found in the literature that the distance between the
>> interstitial N-N atoms is around 1.4 A.
>> These results were for GaNAs, not for GaNP, but I guess that the
>> distances will not be much different in those materials.
>> So, in any case I am forced to reduce the RMTs and accordingly change
>> the cut-off energy.
>> Just now I am trying to relax the supercell taking RMT(Ga,P)=1.5, 
>> RMT(N)=1.1  and  10Ry.
>> 
>
> The manual does advise as large an RMT as you can manage but if your N atoms 
> are 1.4 apart and the RMT of N is 1.1, will not the cores overlap? The bond 
> distance in the free molecule is 1.1. You may need to use an even smaller 
> RMT. Of course very small RMTs do pose problems.
>
>
>   
>> As you mentioned, this value is rather usual and it was very useful
>> information for me.
>> Thank you very much for advices.
>> 
>
> I hope your runs are now successful.
>
> Elaine
>
>   
>> Best wishes,
>> Kakha
>> 
>
>
>
>
> Lyudmila V. Dobysheva wrote:
>   
>>> Here is the "correct" structure file:
>>> 
>>>   
>> Dear Kakha,
>>
>> I'd first make optimization of the cell parameters: the inserted 2 N atoms 
>> instead of P should certainly expand the lattice in one direction, and maybe 
>> reduce, maybe also expand in the two other directions. So, you'll receive 
>> different c and a=b  (according to your struct file given).
>> I am sure that after this you'll have a liitle more space for N atoms and 
>> further optimization of the atoms position may be possible. If it 
>> is not enough, than you should really decrease the Rmt's and, in order to 
>> avoid the leakage from core, insert some core levels into the valence 
>> basis. 10 Ry which you have mentioned is rather usual  as a limit for the 
>> separation in such calculations.
>>
>> Best wishes
>> Lyudmila Dobysheva
>> --
>> Phys.-Techn. Institute of Ural Br. of Russian Ac. of Sci.
>> 426001 Izhevsk, ul.Kirova 132
>> RUSSIA
>> --
>> Tel.:7(3412) 442118 (home), 218988(office), 250614(Fax)
>> E-mail: lyu at otf.fti.udmurtia.su
>> lyuka17 at mail.ru
>> lyu at otf.pti.udm.ru
>> http://fti.udm.ru/content/view/25/103/lang,english/
>> --
>> ___
>> Wien mailing list
>> Wien at zeus.theochem.tuwien.ac.at
>> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
>>
>>   
>> 
>
> ___
> Wien mailing list
> Wien at zeus.theochem.tuwien.ac.at
> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
>
>   

[Wien] Interstitial N-N pair in GaP supercell

[E.A.Moore]

-Original Message-
From: Kakhaber Jandieri [mailto:kakhaber.jandi...@physik.uni-marburg.de] 
Sent: 06 July 2010 15:28
To: A Mailing list for WIEN2k users
Subject: Re: [Wien] Interstitial N-N pair in GaP supercell


>My final goal is to study the influence of these interstitial structures
>on the structural factor.
>Of course, the lattice parameters will be changed and it will have the
>influence on the structural factor along with influence of atom
>displacements.

I would have thought the local atom displacements would be more important than 
the change in lattice constants. I assume your supercell is chosen so that 
there is little or no N2-N2 interaction.

>But, as far as I know,  the determination of lattice parameters is more
>time-consuming task.
>So on preliminary stage I decided to try the supercell with unchanged
>lattice constants but with relaxed atom positions.
>It was just interesting for me to see what happens.
>Depending on the results, I will try to determine the lattice constants
>and then relax the supercell.
>Anyway, I found in the literature that the distance between the
>interstitial N-N atoms is around 1.4 A.
>These results were for GaNAs, not for GaNP, but I guess that the
>distances will not be much different in those materials.
>So, in any case I am forced to reduce the RMTs and accordingly change
>the cut-off energy.
>Just now I am trying to relax the supercell taking RMT(Ga,P)=1.5, 
>RMT(N)=1.1  and  10Ry.

The manual does advise as large an RMT as you can manage but if your N atoms 
are 1.4 apart and the RMT of N is 1.1, will not the cores overlap? The bond 
distance in the free molecule is 1.1. You may need to use an even smaller RMT. 
Of course very small RMTs do pose problems.


>As you mentioned, this value is rather usual and it was very useful
>information for me.
>Thank you very much for advices.

I hope your runs are now successful.

Elaine

>Best wishes,
>Kakha




Lyudmila V. Dobysheva wrote:
>> Here is the "correct" structure file:
>> 
>
> Dear Kakha,
>
> I'd first make optimization of the cell parameters: the inserted 2 N atoms 
> instead of P should certainly expand the lattice in one direction, and maybe 
> reduce, maybe also expand in the two other directions. So, you'll receive 
> different c and a=b  (according to your struct file given).
> I am sure that after this you'll have a liitle more space for N atoms and 
> further optimization of the atoms position may be possible. If it 
> is not enough, than you should really decrease the Rmt's and, in order to 
> avoid the leakage from core, insert some core levels into the valence 
> basis. 10 Ry which you have mentioned is rather usual  as a limit for the 
> separation in such calculations.
>
> Best wishes
> Lyudmila Dobysheva
> --
> Phys.-Techn. Institute of Ural Br. of Russian Ac. of Sci.
> 426001 Izhevsk, ul.Kirova 132
> RUSSIA
> --
> Tel.:7(3412) 442118 (home), 218988(office), 250614(Fax)
> E-mail: lyu at otf.fti.udmurtia.su
> lyuka17 at mail.ru
> lyu at otf.pti.udm.ru
> http://fti.udm.ru/content/view/25/103/lang,english/
> --
> ___
> Wien mailing list
> Wien at zeus.theochem.tuwien.ac.at
> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
>
>   

___
Wien mailing list
Wien at zeus.theochem.tuwien.ac.at
http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien

-- 
The Open University is incorporated by Royal Charter (RC 000391), an exempt 
charity in England & Wales and a charity registered in Scotland (SC 038302).

[Wien] Interstitial N-N pair in GaP supercell

[Kakhaber Jandieri]

Dear Lyudmila,

My final goal is to study the influence of these interstitial structures
on the structural factor.
Of course, the lattice parameters will be changed and it will have the
influence on the structural factor along with influence of atom
displacements.
But, as far as I know,  the determination of lattice parameters is more
time-consuming task.
So on preliminary stage I decided to try the supercell with unchanged
lattice constants but with relaxed atom positions.
It was just interesting for me to see what happens.
Depending on the results, I will try to determine the lattice constants
and then relax the supercell.
Anyway, I found in the literature that the distance between the
interstitial N-N atoms is around 1.4 A.
These results were for GaNAs, not for GaNP, but I guess that the
distances will not be much different in those materials.
So, in any case I am forced to reduce the RMTs and accordingly change
the cut-off energy.
Just now I am trying to relax the supercell taking RMT(Ga,P)=1.5, 
RMT(N)=1.1  and  10Ry.
As you mentioned, this value is rather usual and it was very useful
information for me.
Thank you very much for advices.

Best wishes,
Kakha




Lyudmila V. Dobysheva wrote:
>> Here is the "correct" structure file:
>> 
>
> Dear Kakha,
>
> I'd first make optimization of the cell parameters: the inserted 2 N atoms 
> instead of P should certainly expand the lattice in one direction, and maybe 
> reduce, maybe also expand in the two other directions. So, you'll receive 
> different c and a=b  (according to your struct file given).
> I am sure that after this you'll have a liitle more space for N atoms and 
> further optimization of the atoms position may be possible. If it 
> is not enough, than you should really decrease the Rmt's and, in order to 
> avoid the leakage from core, insert some core levels into the valence 
> basis. 10 Ry which you have mentioned is rather usual  as a limit for the 
> separation in such calculations.
>
> Best wishes
> Lyudmila Dobysheva
> --
> Phys.-Techn. Institute of Ural Br. of Russian Ac. of Sci.
> 426001 Izhevsk, ul.Kirova 132
> RUSSIA
> --
> Tel.:7(3412) 442118 (home), 218988(office), 250614(Fax)
> E-mail: lyu at otf.fti.udmurtia.su
> lyuka17 at mail.ru
> lyu at otf.pti.udm.ru
> http://fti.udm.ru/content/view/25/103/lang,english/
> --
> ___
> Wien mailing list
> Wien at zeus.theochem.tuwien.ac.at
> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
>
>   

[Wien] Interstitial N-N pair in GaP supercell

[Lyudmila V. Dobysheva]

> Here is the "correct" structure file:

Dear Kakha,

I'd first make optimization of the cell parameters: the inserted 2 N atoms 
instead of P should certainly expand the lattice in one direction, and maybe 
reduce, maybe also expand in the two other directions. So, you'll receive 
different c and a=b  (according to your struct file given).
I am sure that after this you'll have a liitle more space for N atoms and 
further optimization of the atoms position may be possible. If it 
is not enough, than you should really decrease the Rmt's and, in order to 
avoid the leakage from core, insert some core levels into the valence 
basis. 10 Ry which you have mentioned is rather usual  as a limit for the 
separation in such calculations.

Best wishes
Lyudmila Dobysheva
--
Phys.-Techn. Institute of Ural Br. of Russian Ac. of Sci.
426001 Izhevsk, ul.Kirova 132
RUSSIA
--
Tel.:7(3412) 442118 (home), 218988(office), 250614(Fax)
E-mail: lyu at otf.fti.udmurtia.su
lyuka17 at mail.ru
lyu at otf.pti.udm.ru
http://fti.udm.ru/content/view/25/103/lang,english/
--

[Wien] Interstitial N-N pair in GaP supercell

[Kakhaber Jandieri]

Dear Elaine,

Excuse me.
In my previous letter by mistake I showed the structure file for relaxed
GaBAs supercell, not for GaNP.
Here is the "correct" structure file:

Title  

P   16 111 P-42m 
 RELA
 20.60 20.60 20.60 90.00 90.00 90.00
ATOM  -1: X=0.74981056 Y=0.74981056 Z=0.99974365
  MULT= 4  ISPLIT= 8
  -1: X=0.25018944 Y=0.25018944 Z=0.99974365
  -1: X=0.74981056 Y=0.25018944 Z=0.00025635
  -1: X=0.25018944 Y=0.74981056 Z=0.00025635
P 1NPT=  781  R0=0.0001 RMT=2.   Z:  15.0
LOCAL ROT MATRIX:0.000-0.7071068-0.7071068
 0.000-0.7071068 0.7071068
-1.000 0.000 0.000
ATOM  -2: X=0.75459268 Y=0.75459268 Z=0.49899362
  MULT= 4  ISPLIT= 8
  -2: X=0.24540732 Y=0.24540732 Z=0.49899362
  -2: X=0.75459268 Y=0.24540732 Z=0.50100638
  -2: X=0.24540732 Y=0.75459268 Z=0.50100638
P 2NPT=  781  R0=0.0001 RMT=2.   Z:  15.0
LOCAL ROT MATRIX:0.000-0.7071068-0.7071068
 0.000-0.7071068 0.7071068
-1.000 0.000 0.000
ATOM  -3: X=0. Y=0. Z=0.
  MULT= 1  ISPLIT=-2
P 3NPT=  781  R0=0.0001 RMT=2.   Z:  15.0
LOCAL ROT MATRIX:1.000 0.000 0.000
 0.000 1.000 0.000
 0.000 0.000 1.000
ATOM  -4: X=0. Y=0.5000 Z=0.
  MULT= 2  ISPLIT= 8
  -4: X=0.5000 Y=0. Z=0.
P 4NPT=  781  R0=0.0001 RMT=2.   Z:  15.0
LOCAL ROT MATRIX:1.000 0.000 0.000
 0.000 1.000 0.000
 0.000 0.000 1.000
ATOM  -5: X=0.5000 Y=0.5000 Z=0.
  MULT= 1  ISPLIT=-2
P 5NPT=  781  R0=0.0001 RMT=2.   Z:  15.0
LOCAL ROT MATRIX:1.000 0.000 0.000
 0.000 1.000 0.000
 0.000 0.000 1.000
ATOM  -6: X=0.00057358 Y=0.74740389 Z=0.75264594
  MULT= 8  ISPLIT= 8
  -6: X=0.99942642 Y=0.25259611 Z=0.75264594
  -6: X=0.74740389 Y=0.99942642 Z=0.24735406
  -6: X=0.25259611 Y=0.00057358 Z=0.24735406
  -6: X=0.99942642 Y=0.74740389 Z=0.24735406
  -6: X=0.00057358 Y=0.25259611 Z=0.24735406
  -6: X=0.25259611 Y=0.99942642 Z=0.75264594
  -6: X=0.74740389 Y=0.00057358 Z=0.75264594
P 6NPT=  781  R0=0.0001 RMT=2.   Z:  15.0
LOCAL ROT MATRIX:1.000 0.000 0.000
 0.000 1.000 0.000
 0.000 0.000 1.000
ATOM  -7: X=0. Y=0.5000 Z=0.5000
  MULT= 2  ISPLIT= 8
  -7: X=0.5000 Y=0. Z=0.5000
P 7NPT=  781  R0=0.0001 RMT=2.   Z:  15.0
LOCAL ROT MATRIX:1.000 0.000 0.000
 0.000 1.000 0.000
 0.000 0.000 1.000
ATOM  -8: X=0.5000 Y=0.5000 Z=0.5000
  MULT= 1  ISPLIT=-2
P 8NPT=  781  R0=0.0001 RMT=2.   Z:  15.0
LOCAL ROT MATRIX:1.000 0.000 0.000
 0.000 1.000 0.000
 0.000 0.000 1.000
ATOM  -9: X=0.75007802 Y=0.50013518 Z=0.25006534
  MULT= 8  ISPLIT= 8
  -9: X=0.24992198 Y=0.49986482 Z=0.25006534
  -9: X=0.50013518 Y=0.24992198 Z=0.74993466
  -9: X=0.49986482 Y=0.75007802 Z=0.74993466
  -9: X=0.24992198 Y=0.50013518 Z=0.74993466
  -9: X=0.75007802 Y=0.49986482 Z=0.74993466
  -9: X=0.49986482 Y=0.24992198 Z=0.25006534
  -9: X=0.50013518 Y=0.75007802 Z=0.25006534
P 9NPT=  781  R0=0.0001 RMT=2.   Z:  15.0
LOCAL ROT MATRIX:1.000 0.000 0.000
 0.000 1.000 0.000
 0.000 0.000 1.000
ATOM -10: X=0. Y=0. Z=0.56080648
  MULT= 2  ISPLIT= 8
 -10: X=0. Y=0. Z=0.43919352
N 1NPT=  781  R0=0.0001 RMT=1.2000   Z:   7.0
LOCAL ROT MATRIX:0.7071068 0.7071068 0.000
-0.7071068 0.7071068 0.000
 0.000 0.000 1.000
ATOM -11: X=0.87467841 Y=0.87467841 Z=0.12520722
  MULT= 4  ISPLIT= 8
 -11: X=0.12532159 Y=0.12532159 Z=0.12520722
 -11: X=0.87467841 Y=0.12532159 Z=0.87479278
 -11: X=0.12532159 Y=0.87467841 Z=0.87479278
Ga1NPT=  781  R0=0.0001 RMT=2.   Z:  31.0
LOCAL ROT MATRIX:0.000-0.7071068-0.7071068
 0.000-0.7071068 0.7071068
-1.000 0.000 0.

[Wien] Interstitial N-N pair in GaP supercell

[Kakhaber Jandieri]

13581 Z=0.12494606
  -8: X=0.87505394 Y=0.62513581 Z=0.87505394
  -8: X=0.12494606 Y=0.37486419 Z=0.87505394
  -8: X=0.87505394 Y=0.37486419 Z=0.12494606
As2NPT=  781  R0=0.5000 RMT=2.   Z:  33.0
LOCAL ROT MATRIX:0.000-0.7071068-0.7071068
 0.000-0.7071068 0.7071068
-1.000 0.000 0.000
ATOM  -9: X=0.37283866 Y=0.12444999 Z=0.37283866
  MULT=12  ISPLIT= 8
  -9: X=0.62716134 Y=0.87555001 Z=0.37283866
  -9: X=0.62716134 Y=0.12444999 Z=0.62716134
  -9: X=0.37283866 Y=0.87555001 Z=0.62716134
  -9: X=0.37283866 Y=0.37283866 Z=0.12444999
  -9: X=0.37283866 Y=0.62716134 Z=0.87555001
  -9: X=0.62716134 Y=0.62716134 Z=0.12444999
  -9: X=0.62716134 Y=0.37283866 Z=0.87555001
  -9: X=0.12444999 Y=0.37283866 Z=0.37283866
  -9: X=0.87555001 Y=0.37283866 Z=0.62716134
  -9: X=0.12444999 Y=0.62716134 Z=0.62716134
  -9: X=0.87555001 Y=0.62716134 Z=0.37283866
As3NPT=  781  R0=0.5000 RMT=2.   Z:  33.0
LOCAL ROT MATRIX:0.000-0.7071068-0.7071068
 1.000 0.000 0.000
 0.000-0.7071068 0.7071068
ATOM -10: X=0.62498650 Y=0.62498650 Z=0.62498650
  MULT= 4  ISPLIT= 4
 -10: X=0.37501350 Y=0.37501350 Z=0.62498650
 -10: X=0.37501350 Y=0.62498650 Z=0.37501350
 -10: X=0.62498650 Y=0.37501350 Z=0.37501350
As4NPT=  781  R0=0.5000 RMT=2.   Z:  33.0
LOCAL ROT MATRIX:0.4082483-0.7071068 0.5773503
 0.4082483 0.7071068 0.5773503
-0.8164966 0.000 0.5773503 


As I wrote in my previous letters, my main problem is in RMTs. The
distance between N atoms in N-N interstitial pair is small - slightly
larger then that in isolated N2 molecule
(some about 1.4-1.5 A). So, I am forced to take for N atoms 
RMT(N)=1.0-1.2, while for Ga and P atoms RMT(P,Ga)=1.8-2.0. The
difference between these values is extremely large that should not be
the case (according to the User Guide).
In my opinion the only choice is to reduce  RMT(P,Ga)  and to take the*
*separation energy between core and valence states equal to -10Ry,
though this value is much lower then recommended value -6 Ry.
Are my suggestions reasonable or I am on the wrong way?

Thank you once again.

Kakha

E.A.Moore wrote:
> If you want to study a pair of interstitial N atoms, you must add two N 
> atoms, not replace P. Or if you are replacing P by two interstitial N atoms, 
> you remove one P and add two N at new positions. 
> Interstitial means the atoms are not on lattice sites. 
> If the reduced cell has 16 inequivalent atoms, it sounds as  though you have 
> 64 not 65 atoms, so possibly you have just replaced P by N on four sites. 
>
> Are you trying to add an interstitial N2 molecule? If not why do you need two 
> N atoms?
>
> Elaine A. Moore
>
> 
> From: Kakhaber Jandieri [Kakhaber.Jandieri at physik.uni-marburg.de]
> Sent: 04 July 2010 15:04
> To: A Mailing list for WIEN2k users
> Subject: Re: [Wien] Interstitial N-N pair in GaP supercell
>
> Dear Swati,
>
> Thank you for advice, but I still want to clarify some questions:
>
> "first of all I think you can't replace one atom by a pair of atoms".
>
> My final goal is to obtain the relaxed atom positions in GaP supercell
> where one of the P atoms is replaced by the interstitial pair of
> Nitrogen-Nitrogen atoms.
> To say truth, I am not sure in correctness of my approach but I did the
> following:
> Step1 - Using the program "supercell" I generated 2x2x2 supercell for
> GaP containing 64 atoms
> Step2 -  I construct a new supercell with 64  inequivalent atoms using
> the positions obtained in Step1
> Step3 -  I split one P atom in 2 atoms
> Step4 -  I changed the atoms obtained in Step3 from P to N
> Step5 -  I ran "x sgroup". It converted my "p" supercell with 65
> inequivalent atoms into the "111_p-42m" supercell with 16 inequivalent atoms
> Step6 - I ran the program "mini".
>
> Could you advice me the correct way for constructing the supercell with
> interstitial pair of  N-N atoms in  GaP matrix?
>
>
> "Set 5% less RMT for all types of atoms instead of reduction of RMT of N
> only and run mini"
>
> In interstitial N-N pair the interatomic distance between N atoms might be 
> significantly smaller then the distance between Ga and P atoms.
>
> If instead of 2.0 I take 5% less RMT, then how cam I prevent the overlapping 
> of spheres between the N atoms in the interstitial pair?
>
>
> Beforehand thankfull,
> Kakha
>
>
>
>
>
> swati chaudhury wrote:
>   
>> Hello,
>> first of all I think you can't rep

[Wien] Interstitial N-N pair in GaP supercell

[E.A.Moore]

If you want to study a pair of interstitial N atoms, you must add two N atoms, 
not replace P. Or if you are replacing P by two interstitial N atoms, you 
remove one P and add two N at new positions. 
Interstitial means the atoms are not on lattice sites. 
If the reduced cell has 16 inequivalent atoms, it sounds as  though you have 64 
not 65 atoms, so possibly you have just replaced P by N on four sites. 

Are you trying to add an interstitial N2 molecule? If not why do you need two N 
atoms?

Elaine A. Moore


From: Kakhaber Jandieri [kakhaber.jandi...@physik.uni-marburg.de]
Sent: 04 July 2010 15:04
To: A Mailing list for WIEN2k users
Subject: Re: [Wien] Interstitial N-N pair in GaP supercell

Dear Swati,

Thank you for advice, but I still want to clarify some questions:

"first of all I think you can't replace one atom by a pair of atoms".

My final goal is to obtain the relaxed atom positions in GaP supercell
where one of the P atoms is replaced by the interstitial pair of
Nitrogen-Nitrogen atoms.
To say truth, I am not sure in correctness of my approach but I did the
following:
Step1 - Using the program "supercell" I generated 2x2x2 supercell for
GaP containing 64 atoms
Step2 -  I construct a new supercell with 64  inequivalent atoms using
the positions obtained in Step1
Step3 -  I split one P atom in 2 atoms
Step4 -  I changed the atoms obtained in Step3 from P to N
Step5 -  I ran "x sgroup". It converted my "p" supercell with 65
inequivalent atoms into the "111_p-42m" supercell with 16 inequivalent atoms
Step6 - I ran the program "mini".

Could you advice me the correct way for constructing the supercell with
interstitial pair of  N-N atoms in  GaP matrix?


"Set 5% less RMT for all types of atoms instead of reduction of RMT of N
only and run mini"

In interstitial N-N pair the interatomic distance between N atoms might be 
significantly smaller then the distance between Ga and P atoms.

If instead of 2.0 I take 5% less RMT, then how cam I prevent the overlapping of 
spheres between the N atoms in the interstitial pair?


Beforehand thankfull,
Kakha





swati chaudhury wrote:
> Hello,
> first of all I think you can't replace one atom by a pair of atoms.
> Set 5% less RMT for all types of atoms instead of reduction of RMT of N only 
> and run mini.
> best wishes.
> swati
>
> --- On Sun, 4/7/10, Kakhaber Jandieri  physik.uni-marburg.de> wrote:
>
>
>> From: Kakhaber Jandieri 
>> Subject: [Wien] Interstitial N-N pair in GaP supercell
>> To: wien at zeus.theochem.tuwien.ac.at
>> Date: Sunday, 4 July, 2010, 5:17 PM
>> In addition to my previous letter.
>>
>> I thought that may be the problem is in very large
>> difference between the RMT(Ga,P)=2.0 and RMT (N)=1.0, but I
>> cannot increase the RMT(N) because
>> of overlapping spheres and, on the other hand, I cannot
>> decrease the RMT(Ga,P) because of charge leakage.
>>
>>
>> Could somebody advice the solution of this problem?
>>
>> I will be extremely thankful for any suggestion.
>>
>> ___
>> Wien mailing list
>> Wien at zeus.theochem.tuwien.ac.at
>> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
>>
>>
> ___
> Wien mailing list
> Wien at zeus.theochem.tuwien.ac.at
> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
>
>

___
Wien mailing list
Wien at zeus.theochem.tuwien.ac.at
http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien

-- 
The Open University is incorporated by Royal Charter (RC 000391), an exempt 
charity in England & Wales and a charity registered in Scotland (SC 038302).

[Wien] Interstitial N-N pair in GaP supercell

[shamik chakrabarti]

Dear Kakhaber Jandieri Sir,

First of all I am sorry because I am
not able to answer your question instead of I am humbelly asking you a
question. You have replaced one P atom by a pair of N atom.
I am interested to know that how do you able to replace one atom by two
atoms?

With regards,

On Sun, Jul 4, 2010 at 5:17 PM, Kakhaber Jandieri <
Kakhaber.Jandieri at physik.uni-marburg.de> wrote:

> In addition to my previous letter.
>
> I thought that may be the problem is in very large difference between the
> RMT(Ga,P)=2.0 and RMT (N)=1.0, but I cannot increase the RMT(N) because
> of overlapping spheres and, on the other hand, I cannot decrease the
> RMT(Ga,P) because of charge leakage.
>
>
> Could somebody advice the solution of this problem?
>
> I will be extremely thankful for any suggestion.
>
> ___
> Wien mailing list
> Wien at zeus.theochem.tuwien.ac.at
> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
>



-- 
Shamik Chakrabarti
Research Scholar
Dept. of Physics & Meteorology
Material Processing & Solid State Ionics Lab
IIT Kharagpur
Kharagpur 721302
INDIA
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[Wien] Interstitial N-N pair in GaP supercell

[Kakhaber Jandieri]

Dear Shamik,

"You have replaced one P atom by a pair of N atom.
I am interested to know that how do you able to replace one atom by two
atoms?"

I described in details the corresponding procedures in my reply to Swati 
Chaudhury.
I already mentioned in this reply that I am not sure in the correctness of 
these procedures, but just now I do not know the correct alternative.

Best wishes,
Kakha





shamik chakrabarti wrote:
> Dear Kakhaber Jandieri Sir,
>
> First of all I am sorry because I am
> not able to answer your question instead of I am humbelly asking you a
> question. You have replaced one P atom by a pair of N atom.
> I am interested to know that how do you able to replace one atom by two
> atoms?
>
> With regards,
>
> On Sun, Jul 4, 2010 at 5:17 PM, Kakhaber Jandieri <
> Kakhaber.Jandieri at physik.uni-marburg.de> wrote:
>
>   
>> In addition to my previous letter.
>>
>> I thought that may be the problem is in very large difference between the
>> RMT(Ga,P)=2.0 and RMT (N)=1.0, but I cannot increase the RMT(N) because
>> of overlapping spheres and, on the other hand, I cannot decrease the
>> RMT(Ga,P) because of charge leakage.
>>
>>
>> Could somebody advice the solution of this problem?
>>
>> I will be extremely thankful for any suggestion.
>>
>> ___
>> Wien mailing list
>> Wien at zeus.theochem.tuwien.ac.at
>> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
>>
>> 
>
>
>
>   
> 
>
> ___
> Wien mailing list
> Wien at zeus.theochem.tuwien.ac.at
> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
>   

[Wien] Interstitial N-N pair in GaP supercell

[Kakhaber Jandieri]

Dear Swati,

Thank you for advice, but I still want to clarify some questions:

"first of all I think you can't replace one atom by a pair of atoms".

My final goal is to obtain the relaxed atom positions in GaP supercell
where one of the P atoms is replaced by the interstitial pair of 
Nitrogen-Nitrogen atoms.
To say truth, I am not sure in correctness of my approach but I did the
following:
Step1 - Using the program "supercell" I generated 2x2x2 supercell for
GaP containing 64 atoms
Step2 -  I construct a new supercell with 64  inequivalent atoms using
the positions obtained in Step1
Step3 -  I split one P atom in 2 atoms
Step4 -  I changed the atoms obtained in Step3 from P to N
Step5 -  I ran "x sgroup". It converted my "p" supercell with 65
inequivalent atoms into the "111_p-42m" supercell with 16 inequivalent atoms
Step6 - I ran the program "mini".

Could you advice me the correct way for constructing the supercell with
interstitial pair of  N-N atoms in  GaP matrix?


"Set 5% less RMT for all types of atoms instead of reduction of RMT of N
only and run mini"

In interstitial N-N pair the interatomic distance between N atoms might be 
significantly smaller then the distance between Ga and P atoms.

If instead of 2.0 I take 5% less RMT, then how cam I prevent the overlapping of 
spheres between the N atoms in the interstitial pair?


Beforehand thankfull,
Kakha 

 



swati chaudhury wrote:
> Hello,
> first of all I think you can't replace one atom by a pair of atoms.
> Set 5% less RMT for all types of atoms instead of reduction of RMT of N only 
> and run mini.
> best wishes.
> swati
>
> --- On Sun, 4/7/10, Kakhaber Jandieri  physik.uni-marburg.de> wrote:
>
>   
>> From: Kakhaber Jandieri 
>> Subject: [Wien] Interstitial N-N pair in GaP supercell
>> To: wien at zeus.theochem.tuwien.ac.at
>> Date: Sunday, 4 July, 2010, 5:17 PM
>> In addition to my previous letter. 
>>
>> I thought that may be the problem is in very large
>> difference between the RMT(Ga,P)=2.0 and RMT (N)=1.0, but I
>> cannot increase the RMT(N) because 
>> of overlapping spheres and, on the other hand, I cannot
>> decrease the RMT(Ga,P) because of charge leakage. 
>>
>>
>> Could somebody advice the solution of this problem?
>>
>> I will be extremely thankful for any suggestion.
>>
>> ___
>> Wien mailing list
>> Wien at zeus.theochem.tuwien.ac.at
>> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
>>
>> 
> ___
> Wien mailing list
> Wien at zeus.theochem.tuwien.ac.at
> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
>
>   

[Wien] Interstitial N-N pair in GaP supercell

[Kakhaber Jandieri]

In addition to my previous letter. 

I thought that may be the problem is in very large difference between the 
RMT(Ga,P)=2.0 and RMT (N)=1.0, but I cannot increase the RMT(N) because 
of overlapping spheres and, on the other hand, I cannot decrease the RMT(Ga,P) 
because of charge leakage. 


Could somebody advice the solution of this problem?

I will be extremely thankful for any suggestion.

[Wien] Interstitial N-N pair in GaP supercell

[Kakhaber Jandieri]

Dear Wien2k users!


I am trying to minimize the GaP supercell with Nitrogen-Nitrogen interstitial 
pair using 
min -i 100 -s 10 -j 'run_lapw -p -I -i 40 -ec 0.001 -fc 1.0 -cc 0.001'
I constructed the supercell with 64 atoms and replaced one P atom  by the pair 
of interstitial N atoms.
After 16 cycles the program stopped with following message:


. . . . . . . . . . .

in cycle 16ETEST: .0996   CTEST: -.0009901

ec cc and fc_conv 1 1 1

 

>   stop

Fallback to compatibility mode with "old" save_lapw

broyden files deleted, clm*, dmat*, vorb*, vresp*, eece*, scf and struct files 
saved under GaPNN_1

27.977u 0.412s 0:28.89 98.2%   0+0k 0+20648io 0pf+0w

0.844u 0.336s 0:01.66 70.4%0+0k 1272+16896io 8pf+0w

clmextrapol_lapw has generated a new GaPNN.clmsum

 

and calculations were renewed.
Further, after 12 cycles, the program stopped again with the message:

 . . . . . . . .
in cycle 12ETEST: .0406   CTEST: -.0009842

ec cc and fc_conv 1 1 1

 

>   stop

 :WARNING: Step size reduced due to overlapping spheres -- check RMT

28.185u 0.408s 0:29.11 98.1%   0+0k 0+20648io 0pf+0w

0.872u 0.320s 0:01.53 77.7%0+0k 0+16896io 0pf+0w

clmextrapol_lapw has generated a new GaPNN.clmsum

 

and so on without ending.
Initially the RMTs for Ga and P atoms were RMT(Ga,P)=2.0  and  for N atom ? 
RMT(N)=1.3
In isolated nitrogen molecule the interatomic distance is approximately 1.295 
Angstrom. 
I guessed that the interatomic distance between the interstitial N atoms in GaP 
supercell would be larger then 1.295 A. 
So I reduced the RMT for N atom and took RMT(N)=1.0, aiming to prevent the 
overlapping of spheres for N-N pair. (2*RMT(N)=1.06 A < 1.295 A). 
In spite of that, the result of ?mini? remains the same ? the interatomic 
distance between the interstitial N atoms becomes even smaller (!!!) then that 
in
isolated nitrogen molecule and I still have the problem with overlapping 
spheres. 

[Wien] Interstitial N-N pair in GaP supercell

[swati chaudhury]

Hello,
first of all I think you can't replace one atom by a pair of atoms.
Set 5% less RMT for all types of atoms instead of reduction of RMT of N only 
and run mini.
best wishes.
swati

--- On Sun, 4/7/10, Kakhaber Jandieri  wrote:

> From: Kakhaber Jandieri 
> Subject: [Wien] Interstitial N-N pair in GaP supercell
> To: wien at zeus.theochem.tuwien.ac.at
> Date: Sunday, 4 July, 2010, 5:17 PM
> In addition to my previous letter. 
> 
> I thought that may be the problem is in very large
> difference between the RMT(Ga,P)=2.0 and RMT (N)=1.0, but I
> cannot increase the RMT(N) because 
> of overlapping spheres and, on the other hand, I cannot
> decrease the RMT(Ga,P) because of charge leakage. 
> 
> 
> Could somebody advice the solution of this problem?
> 
> I will be extremely thankful for any suggestion.
> 
> ___
> Wien mailing list
> Wien at zeus.theochem.tuwien.ac.at
> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
>