Re: [Wien] BerryPi

[Oleg Rubel]

Just a small addition: It is a “must" to start with the least symmetric 
structure first. This implies that you need to introduce displacements, 
init_lapw, run(sp)_lapw, berrypy and then bring atoms back to the high symmetry 
position, dstart (-up/-dn), run(sp)_lapw, berrypi.

In your structure alpha and beta are 90 deg. If you are interested in Z*(3,3) 
(i.e., along Z axis) then there is no need to worry about nonorthogonality of 
lattice vectors, similar to 
https://github.com/spichardo/BerryPI/wiki/Tutorial-4:-Polarization-in-GaN

Please be cautious with the band occupancy. Can you list the results of “grep 
:BAN *scf”? If the structure is metallic, berrypi cannot be continued.

Oleg

> On Jan 29, 2016, at 05:59, Dr. K. C. Bhamu  wrote:
> 
> What you need it to shift both position i.e. 0.5 to 0.501 and 
> 0. to 0.0010.
> 
> Problem will be solved.
> 
> regards
> 
> 
> 
> 
> Dr. K. C. Bhamu
> (UGC-Dr. D. S. Kothari Postdoc Fellow)
> Department of Physics
> Goa University, Goa-403 206
> India
> Mob. No.  +91-9782911977
> 
> On Fri, Jan 29, 2016 at 3:59 PM, lokanath patra  
> wrote:
> Dear Fecher and Bhamu,
> I also think that the error is due to the symmetry after changing the struct 
> file. But the tutorial says ''Do not rerun the init_lapw as it may realize a 
> higher symmetry. The intention is to keep symmetry unchanged between 
> subsequent runs''. Just check the 3rd and 4 points of the link. 
> https://github.com/spichardo/BerryPI/wiki/Tutorial-3:-Non-orthogonal-lattice-vectors
> 
> Thanks.
>  
> 
> On Fri, Jan 29, 2016 at 2:47 PM, Dr. K. C. Bhamu  wrote:
> Hello Lokanath
> I did a mistake in my previous mail regarding rmt issue.
> Your RMT is ok (I did a mistack in compilation).
> 
> your x nn gives error so definitely something is wrong with struct file.
> 
> Experts may help you.
> 
> regards
> Bhamu
> 
> 
> 
> 
> 
> On Fri, Jan 29, 2016 at 11:19 AM, lokanath patra 
>  wrote:
> Dear Dr Bhamu, 
> Actually I have already searched for that. But as  I am changing the position 
> of an atom, I guess the symmetry breaks and the error comes. With the struct 
> file with unchanged atomic position, it runs fine.
> 
> Dear Oleg Rubel,
> 
> Here I am attaching the two struct files used in “initial” calculation and 
> after the displacement is introduced.
> 
> Thanks.
> 
> On Thu, Jan 28, 2016 at 11:29 PM, Oleg Rubel  wrote:
> Would it be possible to attach the structure files used in “initial” 
> calculation and after the displacement is introduced?
> 
> Thank you
> Oleg
> 
> > On Jan 28, 2016, at 11:08, Dr. K. C. Bhamu  wrote:
> >
> > Dear Lokanath
> >
> > Your error is wellknown if you search mailing list.
> > You may try : 
> > https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg08405.html
> >
> > Some time ago I got same error and by compiling SRC_hf agin I overcome the 
> > error.
> >
> > regards
> >
> >
> >
> > 
> > Dr. K. C. Bhamu
> > (UGC-Dr. D. S. Kothari Postdoc Fellow)
> > Department of Physics
> > Goa University, Goa-403 206
> > India
> > Mob. No.  +91-9782911977
> >
> > On Thu, Jan 28, 2016 at 8:33 PM, lokanath patra 
> >  wrote:
> > Dear Users,
> >
> > I am trying to calculate born effective charge for Bi atom in BiFeO3. I 
> > followed the tutorial for GaAs as BiFeO3 is having non orthogonal lattice 
> > vectors. I used berrypi with -s option as it consists of magnetic ion. But 
> > after changing the position of Bi atom by 0.001, when I put the command ''x 
> > dstart'' to initialize the electron density, it is showing 'rot-def' error. 
> > Please help.
> >
> > Thanks in advance.
> >
> > --
> > Lokanath Patra
> > Ph.D Scholar
> > Dept. of Physics
> > School of Applied and Basic Sciences
> > Central University of Tamil Nadu
> > Thiruvarur
> > Tamil Nadu - 610101
> > Ph no - +91-8675834507
> >
> > ___
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> >
> >
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> 
> -- 
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> Ph.D Scholar
> Dept. of Physics
> School of Applied and Basic Sciences
> Central University of Tamil Nadu
> Thiruvarur
> Tamil Nadu - 610101
> Ph no - +91-8675834507
> 
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Re: [Wien] force difference between LAPW and PAW method

[pavel.ondracka]

-- Původní zpráva --
Od: Laurence Marks 
Komu: A Mailing list for WIEN2k users 
Datum: 29. 1. 2016 13:34:23
Předmět: Re: [Wien] force difference between LAPW and PAW method

"

Did you check the absolute cell size for the two - minimize the energy w.r.
t. size?

"



The absolute cell size was fixed (same in both softwares of course) and was 
calculated using experimental densities for the mixtures. No minimization 
with respect to cell volume was done, however I would expect it to be near 
equilibrium. My main goal with those cells is to calculate the XPS shifts of
O1s peak (using the slater transition state method) to help in evaluation of
some experimental XPS data, so I wanted to stick with the experimental 
densities.




Would some stress in the cell explain the difference between the methods?

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Re: [Wien] force difference between LAPW and PAW method

[pavel.ondracka]

-- Původní zpráva --
Od: Peter Blaha 
Komu: A Mailing list for WIEN2k users 
Datum: 29. 1. 2016 12:56:20
Předmět: Re: [Wien] force difference between LAPW and PAW method

"Maybe one should use in VASP also a PAW potential which has Si-2p as 
valence. 
""
"
Thanks for the advice, we will try this. 

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Re: [Wien] force difference between LAPW and PAW method

[Laurence Marks]

Did you check the absolute cell size for the two - minimize the energy
w.r.t. size?

---
Professor Laurence Marks
Department of Materials Science and Engineering
Northwestern University
http://www.numis.northwestern.edu
Corrosion in 4D http://MURI4D.numis.northwestern.edu
Co-Editor, Acta Cryst A
"Research is to see what everybody else has seen, and to think what nobody
else has thought"
Albert Szent-Gyorgi
On Jan 29, 2016 04:38, "Pavel Ondračka"  wrote:

> Laurence Marks píše v Pá 29. 01. 2016 v 04:22 -0600:
> > Did you check for lattice parameter changes? A relatively small
> > change for a single unit cell can translate to something larger.
> > Unfortunately you need a reference compound, which is not so simple
> > in your case. Perhaps test SiO2, TiO2 & a few simple similar
> > compounds with the PAW & Wien2k.
>
> Yeah, some difference in cell size or positions was one of my suspects.
> I usually use VESTA to read the structure file from PAW software, then
> output to cif and use cif2struct to convert to struct and I was
> suspecting that maybe somewhere in this process I lose precision.
> So I've actually written a small python script to convert it directly
> with full precision allowed by the struct format, however the result
> were almost identical.
> Regarding the test cases, we tested eg. with rutile (with one atom
> slightly displaced to induce some forces) and the result were
> comparable (few percent difference).
>
> Best regards
> Pavel Ondračka
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Re: [Wien] force difference between LAPW and PAW method

[Peter Blaha]

Maybe one should use in VASP also a PAW potential which has Si-2p as 
valence.


On 01/29/2016 12:47 PM, pavel.ondra...@email.cz wrote:


-- Původní zpráva --
Od: Peter Blaha 
Komu: A Mailing list for WIEN2k users 
Datum: 29. 1. 2016 12:18:58
Předmět: Re: [Wien] force difference between LAPW and PAW method


If the disordered compound goes metallic ??? it could be a problem. The
default WIEN2k is using TETRA, while VASP uses a large broadening.


The resulting structure has gap at least as large as TiO2.


Again, forget the 400 eV of the PAW calculation. It has NOTHING to do
with our RKmax and our basis sets are usually more efficient.

In any case, RKMAX=8.5 is "more than overconverged", since your
smallest
sphere is probably Oxygen. I'd start such a calculation with RKMAX=5
and
later check with 6 and/or 7.


True, for usual calculations I use value RKMAX around 7.0 for such
compounds, I went to 8.0 just for convergence checking purposes. However
average differences in forces between 7.0 and 8.0 were quite small <
0.2mRyd/Bohr


Another possible problem: SiO2 might have small spheres for Si leading
to quite some core leakage ??? Either use .lcore or put the Si-2p as
semicore !


Indeed I've noticed that silicon gets very small sphere especially with
the new scheme in setrm. I'm using the "original" scheme, where the Si
usually gets same sphere as O, around 1.5. Also Si2-p states were chosen
as semicore. No core leakage warnings in logs.


On 01/29/2016 12:04 PM, Pavel Ondračka wrote:
 > Peter Blaha píše v Pá 29. 01. 2016 v 11:43 +0100:
 >> This looks fairly large.
 >>
 >> I do NOT understand your statement of using "the same RKMAX" ???
 >> PAW does not have RKMAX and their KMAX has NOTHING to do with ours.
 >> What was your RKMAX and what are youre sphere sizes ???
 >
 > Sorry, the right word should probably be "equivalent RKMAX". As
 > mentioned in the original email, the RKMAX was calculated from cutoff
 > in EV using the scheme from userguide (sqrt(cutoff in Ryd) * size of
 > smallest sphere). Specific values differed between cells, smallest
 > spheres were around 1.5 and the RKMAX was around 8.0 (PAW cutoff of
 > 400eV).
 >>
 >> k-mesh: not only the grid is important ! As far as I know, VASP
 >> usually
 >> uses a "huge" temperature broadening. What FERMI-method are you
using
 >> ?
 >
 > default
 >
 >> spin-polarization ??
 >
 > no
 >
 >> Is the PAW done with VASP and a fairly new release (accurate PAW
 >> potentials ?)
 >
 > It was VASP and it was one of the latest versions. Will check for
 > specifics.
 >
 >>
 >> On 01/29/2016 10:50 AM, Pavel Ondračka wrote:
 >>> Dear Wien2k mailing list,
 >>>
 >>> I've been doing some calculation on a moderately large (around 100
 >>> atoms) amorphous-like SixTi1-xO2 cells produced by simulated
 >>> annealing
 >>> MD in a PAW software. According to my colleague who did the final
 >>> force
 >>> relaxation, the residual forces on atoms should be around 0.5
 >>> mRyd/Bohr. However when I calculate forces in Wien2k I see forces
 >>> of
 >>> order of magnitude larger, eg. some as large as 30mRyd/Bohr.
 >>>
 >>> This are exactly the same calculations: both using PBE, same k-
 >>> grid,
 >>> same RKMAX (calculated from cutoff using the formula from UG) and
 >>> I've
 >>> spent a lot of time checking the force convergence with respect to
 >>> all
 >>> possible parameters.
 >>>
 >>> We did some tests with small cells (eg. 10 atoms) and there we can
 >>> get
 >>> a consistent results with max difference of forces around 10-20%
 >>> which
 >>> I find reasonable. I'm actually quite clueless about it. I've been
 >>> suspecting user error at the beginning however I haven't found any
 >>> so
 >>> far. My current theory is that in this large cases without symmetry
 >>> maybe the small differences between methods somehow sum up and
 >>> hence
 >>> the big difference in final forces, however I would like to hear
 >>> your
 >>> opinion in this matter.
 >>>
 >>> Best regards
 >>> Pavel Ondračka
 >>> ___
 >>> Wien mailing list
 >>> Wien@zeus.theochem.tuwien.ac.at
 >>> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
 >>> SEARCH the MAILING-LIST at: http://www.mail-archive.com/wien@zeus.
 >>> theochem.tuwien.ac.at/index.html
 >>>
 >>
 > ___
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http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html
 >

--

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---

Re: [Wien] force difference between LAPW and PAW method

[pavel.ondracka]

-- Původní zpráva --
Od: Peter Blaha 
Komu: A Mailing list for WIEN2k users 
Datum: 29. 1. 2016 12:18:58
Předmět: Re: [Wien] force difference between LAPW and PAW method

"If the disordered compound goes metallic ??? it could be a problem. The 
default WIEN2k is using TETRA, while VASP uses a large broadening."



The resulting structure has gap at least as large as TiO2.

"
Again, forget the 400 eV of the PAW calculation. It has NOTHING to do 
with our RKmax and our basis sets are usually more efficient.

In any case, RKMAX=8.5 is "more than overconverged", since your smallest 
sphere is probably Oxygen. I'd start such a calculation with RKMAX=5 and 
later check with 6 and/or 7."


""
True, for usual calculations I use value RKMAX around 7.0 for such 
compounds, I went to 8.0 just for convergence checking purposes. However 
average differences in forces between 7.0 and 8.0 were quite small < 0.2
mRyd/Bohr

"
Another possible problem: SiO2 might have small spheres for Si leading 
to quite some core leakage ??? Either use .lcore or put the Si-2p as 
semicore !"



Indeed I've noticed that silicon gets very small sphere especially with the 
new scheme in setrm. I'm using the "original" scheme, where the Si usually 
gets same sphere as O, around 1.5. Also Si2-p states were chosen as 
semicore. No core leakage warnings in logs.

"
On 01/29/2016 12:04 PM, Pavel Ondračka wrote:
> Peter Blaha píše v Pá 29. 01. 2016 v 11:43 +0100:
>> This looks fairly large.
>>
>> I do NOT understand your statement of using "the same RKMAX" ???
>> PAW does not have RKMAX and their KMAX has NOTHING to do with ours.
>> What was your RKMAX and what are youre sphere sizes ???
>
> Sorry, the right word should probably be "equivalent RKMAX". As
> mentioned in the original email, the RKMAX was calculated from cutoff
> in EV using the scheme from userguide (sqrt(cutoff in Ryd) * size of
> smallest sphere). Specific values differed between cells, smallest
> spheres were around 1.5 and the RKMAX was around 8.0 (PAW cutoff of
> 400eV).
>>
>> k-mesh: not only the grid is important ! As far as I know, VASP
>> usually
>> uses a "huge" temperature broadening. What FERMI-method are you using
>> ?
>
> default
>
>> spin-polarization ??
>
> no
>
>> Is the PAW done with VASP and a fairly new release (accurate PAW
>> potentials ?)
>
> It was VASP and it was one of the latest versions. Will check for
> specifics.
>
>>
>> On 01/29/2016 10:50 AM, Pavel Ondračka wrote:
>>> Dear Wien2k mailing list,
>>>
>>> I've been doing some calculation on a moderately large (around 100
>>> atoms) amorphous-like SixTi1-xO2 cells produced by simulated
>>> annealing
>>> MD in a PAW software. According to my colleague who did the final
>>> force
>>> relaxation, the residual forces on atoms should be around 0.5
>>> mRyd/Bohr. However when I calculate forces in Wien2k I see forces
>>> of
>>> order of magnitude larger, eg. some as large as 30mRyd/Bohr.
>>>
>>> This are exactly the same calculations: both using PBE, same k-
>>> grid,
>>> same RKMAX (calculated from cutoff using the formula from UG) and
>>> I've
>>> spent a lot of time checking the force convergence with respect to
>>> all
>>> possible parameters.
>>>
>>> We did some tests with small cells (eg. 10 atoms) and there we can
>>> get
>>> a consistent results with max difference of forces around 10-20%
>>> which
>>> I find reasonable. I'm actually quite clueless about it. I've been
>>> suspecting user error at the beginning however I haven't found any
>>> so
>>> far. My current theory is that in this large cases without symmetry
>>> maybe the small differences between methods somehow sum up and
>>> hence
>>> the big difference in final forces, however I would like to hear
>>> your
>>> opinion in this matter.
>>>
>>> Best regards
>>> Pavel Ondračka
>>> ___
>>> Wien mailing list
>>> Wien@zeus.theochem.tuwien.ac.at
>>> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
>>> SEARCH the MAILING-LIST at: http://www.mail-archive.com/wien@zeus.
>>> theochem.tuwien.ac.at/index.html
>>>
>>
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--
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Phone: +43-1-58801-165300 FAX: +43-1-58801-165982
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Re: [Wien] Initialization with spin-orbit

[Islam, Md F]

Thanks, Prof. Blaha. 

Fhokrul  



From: wien-boun...@zeus.theochem.tuwien.ac.at 
[wien-boun...@zeus.theochem.tuwien.ac.at] On Behalf Of Peter Blaha 
[pbl...@theochem.tuwien.ac.at]
Sent: Thursday, January 28, 2016 1:16 PM
To: A Mailing list for WIEN2k users
Subject: Re: [Wien] Initialization with spin-orbit

I can verify the problem.

However, I could not find a fix quickly. Since I'm very busy in the next
2 weeks, it may take some time to debug this completely.

As mentioned before, when SO does not change symmetry (you can see this
in outsymso file if all operations are either type A or B), you can
neglect symmetso.

Am 28.01.2016 um 17:14 schrieb Islam, Md F:
> Hi Prof. Blaha,
>
>  Thanks for your reply. I have sent the structure to your email as you 
> have mentioned.
>
> Regards,
> Fhokrul
>
> 
> From: wien-boun...@zeus.theochem.tuwien.ac.at 
> [wien-boun...@zeus.theochem.tuwien.ac.at] On Behalf Of Peter Blaha 
> [pbl...@theochem.tuwien.ac.at]
> Sent: Tuesday, January 26, 2016 5:11 PM
> To: A Mailing list for WIEN2k users
> Subject: Re: [Wien] Initialization with spin-orbit
>
> Not exactly sure what can cause the problem.
>
> Please search the mailing list, there was some time ago a patch for
> symmetso.
>
>   From your description of the problem (optimized/non-optimized
> structure) it could be a symmetry problem, i.e. during optimization
> (hexagonal case ???) the symmetry of the positions in the struct file
> was slightly broken (rounding errors, something like 0.34 or
> similar ...)
>
> Otherwise you have to send me your struct file.
>
>
>> 1. Is it ok to initialize the job using initso with unrelaxed structure but 
>> after initialization, replace it by relaxed
>>   structure file and run the job?
>
> No, at least not in general as symmetso may/may not reduce symmetry
> depending on the direction of magnetism.
>
>
>> 2. For spin polarized calculations, spin-orbit may reduce the symmetry 
>> depending on the choice of magnetization
>>   direction. According to user guide, initso picks up correct symmetry 
>> for such cases. But if the system does not
>>   have any symmetry to begin with, then is it ok to initialize the 
>> structure treating as non-magnetic case?
>
> Yes, if you are already in P1 you are save and a further reduction of
> symmetry is obviously not possible. Symmetso will not do anything.
>
> However,x kgen -so  (or for P1: x kgen -fbz) is still necessary, as
> for a non-so case, kgen will by default add inversion symmetry to P1,
> which it should not do for a spin-polarized case.
>
> --
> --
> Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
> Phone: +43-1-58801-165300 FAX: +43-1-58801-165982
> Email: bl...@theochem.tuwien.ac.atWIEN2k: http://www.wien2k.at
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> --
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Re: [Wien] force difference between LAPW and PAW method

[Peter Blaha]

If the disordered compound goes metallic ??? it could be a problem. The 
default WIEN2k is using TETRA, while VASP uses a large broadening.


Again, forget the 400 eV of the PAW calculation. It has NOTHING to do 
with our RKmax and our basis sets are usually more efficient.


In any case, RKMAX=8.5 is "more than overconverged", since your smallest 
sphere is probably Oxygen. I'd start such a calculation with RKMAX=5 and 
later check with 6 and/or 7.


Another possible problem: SiO2 might have small spheres for Si leading 
to quite some core leakage ??? Either use .lcore or put the Si-2p as 
semicore !



On 01/29/2016 12:04 PM, Pavel Ondračka wrote:

Peter Blaha píše v Pá 29. 01. 2016 v 11:43 +0100:

This looks fairly large.

I do NOT understand your statement of using "the same RKMAX" ???
PAW does not have RKMAX and their KMAX has NOTHING to do with ours.
What was your RKMAX and what are youre sphere sizes ???


Sorry, the right word should probably be "equivalent RKMAX". As
mentioned in the original email, the RKMAX was calculated from cutoff
in EV using the scheme from userguide (sqrt(cutoff in Ryd) * size of
smallest sphere). Specific values differed between cells, smallest
spheres were around 1.5 and the RKMAX was around 8.0 (PAW cutoff of
400eV).


k-mesh: not only the grid is important ! As far as I know, VASP
usually
uses a "huge" temperature broadening. What FERMI-method are you using
?


default


spin-polarization ??


no


Is the PAW done with VASP and a fairly new release (accurate PAW
potentials ?)


It was VASP and it was one of the latest versions. Will check for
specifics.



On 01/29/2016 10:50 AM, Pavel Ondračka wrote:

Dear Wien2k mailing list,

I've been doing some calculation on a moderately large (around 100
atoms) amorphous-like SixTi1-xO2 cells produced by simulated
annealing
MD in a PAW software. According to my colleague who did the final
force
relaxation, the residual forces on atoms should be around 0.5
mRyd/Bohr. However when I calculate forces in Wien2k I see forces
of
order of magnitude larger, eg. some as large as 30mRyd/Bohr.

This are exactly the same calculations: both using PBE, same k-
grid,
same RKMAX (calculated from cutoff using the formula from UG) and
I've
spent a lot of time checking the force convergence with respect to
all
possible parameters.

We did some tests with small cells (eg. 10 atoms) and there we can
get
a consistent results with max difference of forces around 10-20%
which
I find reasonable. I'm actually quite clueless about it. I've been
suspecting user error at the beginning however I haven't found any
so
far. My current theory is that in this large cases without symmetry
maybe the small differences between methods somehow sum up and
hence
the big difference in final forces, however I would like to hear
your
opinion in this matter.

Best regards
Pavel Ondračka
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Phone: +43-1-58801-165300 FAX: +43-1-58801-165982
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Re: [Wien] force difference between LAPW and PAW method

[Pavel Ondračka]

Peter Blaha píše v Pá 29. 01. 2016 v 11:43 +0100:
> This looks fairly large.
> 
> I do NOT understand your statement of using "the same RKMAX" ???
> PAW does not have RKMAX and their KMAX has NOTHING to do with ours.
> What was your RKMAX and what are youre sphere sizes ???

Sorry, the right word should probably be "equivalent RKMAX". As
mentioned in the original email, the RKMAX was calculated from cutoff
in EV using the scheme from userguide (sqrt(cutoff in Ryd) * size of
smallest sphere). Specific values differed between cells, smallest
spheres were around 1.5 and the RKMAX was around 8.0 (PAW cutoff of
400eV). 
> 
> k-mesh: not only the grid is important ! As far as I know, VASP
> usually 
> uses a "huge" temperature broadening. What FERMI-method are you using
> ?

default

> spin-polarization ??

no

> Is the PAW done with VASP and a fairly new release (accurate PAW 
> potentials ?)

It was VASP and it was one of the latest versions. Will check for
specifics.

> 
> On 01/29/2016 10:50 AM, Pavel Ondračka wrote:
> > Dear Wien2k mailing list,
> > 
> > I've been doing some calculation on a moderately large (around 100
> > atoms) amorphous-like SixTi1-xO2 cells produced by simulated
> > annealing
> > MD in a PAW software. According to my colleague who did the final
> > force
> > relaxation, the residual forces on atoms should be around 0.5
> > mRyd/Bohr. However when I calculate forces in Wien2k I see forces
> > of
> > order of magnitude larger, eg. some as large as 30mRyd/Bohr.
> > 
> > This are exactly the same calculations: both using PBE, same k-
> > grid,
> > same RKMAX (calculated from cutoff using the formula from UG) and
> > I've
> > spent a lot of time checking the force convergence with respect to
> > all
> > possible parameters.
> > 
> > We did some tests with small cells (eg. 10 atoms) and there we can
> > get
> > a consistent results with max difference of forces around 10-20%
> > which
> > I find reasonable. I'm actually quite clueless about it. I've been
> > suspecting user error at the beginning however I haven't found any
> > so
> > far. My current theory is that in this large cases without symmetry
> > maybe the small differences between methods somehow sum up and
> > hence
> > the big difference in final forces, however I would like to hear
> > your
> > opinion in this matter.
> > 
> > Best regards
> > Pavel Ondračka
> > ___
> > Wien mailing list
> > Wien@zeus.theochem.tuwien.ac.at
> > http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
> > SEARCH the MAILING-LIST at:  http://www.mail-archive.com/wien@zeus.
> > theochem.tuwien.ac.at/index.html
> > 
> 
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Re: [Wien] Comparison between ab inito calculation and "measurement" result

[Tomas Kana]

Dear Seongjae, 




 In addition to what Martin has written, I would like to point out that the 
difference between 

the description of a crystal at 0 Kelvin and the same crystal at a room 
temperature 

of 300 K corresponds to the difference between two 

approximations in solid state physics (see e.g. the textbook 

Neil Ashcroft and N. David Mermin, Solid State Physics): 

For 0 K you use the static lattice approximation, 

for 300 K you use the dynamic lattice approximation - it means include 
phonons 

(that can be regarded as quantum units of lattice vibrations, summing them 
up you 

get the whole vibration of your crystal). 

Treating temperature dependent parameters (such as heat capacity) one 
usually 

starts with the static lattice approximation and computing the ground state 
of 

a sufficiently large supercell (using for example the code Wien2k) and 

from there you get the second derivatives (Hessian) of the interatomic 
potentials 

needed to construct the equations valid for the phonons (the dynamic 
matrix). 

In real life this means that after finishing the calculations in Wien2k 

(using the static lattice approximation) you continue with a code like is 
for example 

PHONON by the group of prof. Krystof Parlinski and calculate the quantities 
you 

like to know. 

(see http://www.computingformaterials.com/index.html and others, see 

http://www.wien2k.at/reg_user/unsupported/ after the item Phonon). 

Best regards 

Tomas 






"

Dear group, 




As an engineering researcher with great lack in understanding the ab initio 
calculations, 

I have basically believed that the first-principle calculation results 
demonatrate rather 

"ideal" values presumably obtained at "0 K" and they need to be adjusted by 
proper mathematical 

models formulated as a function of temperature for reachiing the more 
practical values at non-0 K values. 




However, in many pieces of literature, they are trying to compare the ab 
initio calculation 

results and the measurement results at non-0 K, particularly at room 
temperature. 




I'm wondering what sort of foundation is required for believing that the 
simulation results 

can be treated as those obtained at 300 K. In other words, what models or 
equations can be 

adopted for taking the exact band structures and related parameters (Eg, 
effective mass, etc.) 

in hand in performing the first-principle simulations? 




It will be appreciated if you fix my fault and share some wisdom. Many 
thanks. 




- Sincerely, Seongjae. 




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Re: [Wien] BerryPi

[Dr. K. C. Bhamu]

What you need it to shift both position i.e. 0.5 to 0.501 and
0. to 0.0010.

Problem will be solved.

regards









*Dr. K. C. Bhamu(UGC-Dr. D.
S. Kothari Postdoc Fellow)Department of PhysicsGoa University, Goa-403
206IndiaMob. No.  +91-9782911977*

On Fri, Jan 29, 2016 at 3:59 PM, lokanath patra  wrote:

> Dear Fecher and Bhamu,
> I also think that the error is due to the symmetry after changing the
> struct file. But the tutorial says ''Do not rerun the init_lapw as it may
> realize a higher symmetry. The intention is to keep symmetry unchanged
> between subsequent runs''. Just check the 3rd and 4 points of the link.
>
> https://github.com/spichardo/BerryPI/wiki/Tutorial-3:-Non-orthogonal-lattice-vectors
>
> Thanks.
>
>
> On Fri, Jan 29, 2016 at 2:47 PM, Dr. K. C. Bhamu 
> wrote:
>
>> Hello Lokanath
>> I did a mistake in my previous mail regarding rmt issue.
>> Your RMT is ok (I did a mistack in compilation).
>>
>> your *x nn* gives error so definitely something is wrong with struct
>> file.
>>
>>
>> *Experts may help you.*
>> regards
>> Bhamu
>>
>>
>>
>>
>>
>> On Fri, Jan 29, 2016 at 11:19 AM, lokanath patra <
>> lokanath.patra...@gmail.com> wrote:
>>
>>> Dear Dr Bhamu,
>>> Actually I have already searched for that. But as  I am changing the
>>> position of an atom, I guess the symmetry breaks and the error comes. With
>>> the struct file with unchanged atomic position, it runs fine.
>>>
>>> Dear Oleg Rubel,
>>>
>>> Here I am attaching the two struct files used in “initial” calculation
>>> and after the displacement is introduced.
>>>
>>> Thanks.
>>>
>>> On Thu, Jan 28, 2016 at 11:29 PM, Oleg Rubel 
>>> wrote:
>>>
 Would it be possible to attach the structure files used in “initial”
 calculation and after the displacement is introduced?

 Thank you
 Oleg

 > On Jan 28, 2016, at 11:08, Dr. K. C. Bhamu 
 wrote:
 >
 > Dear Lokanath
 >
 > Your error is wellknown if you search mailing list.
 > You may try :
 https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg08405.html
 >
 > Some time ago I got same error and by compiling SRC_hf agin I
 overcome the error.
 >
 > regards
 >
 >
 >
 > 
 > Dr. K. C. Bhamu
 > (UGC-Dr. D. S. Kothari Postdoc Fellow)
 > Department of Physics
 > Goa University, Goa-403 206
 > India
 > Mob. No.  +91-9782911977
 >
 > On Thu, Jan 28, 2016 at 8:33 PM, lokanath patra <
 lokanath.patra...@gmail.com> wrote:
 > Dear Users,
 >
 > I am trying to calculate born effective charge for Bi atom in BiFeO3.
 I followed the tutorial for GaAs as BiFeO3 is having non orthogonal lattice
 vectors. I used berrypi with -s option as it consists of magnetic ion. But
 after changing the position of Bi atom by 0.001, when I put the command ''x
 dstart'' to initialize the electron density, it is showing 'rot-def' error.
 Please help.
 >
 > Thanks in advance.
 >
 > --
 > Lokanath Patra
 > Ph.D Scholar
 > Dept. of Physics
 > School of Applied and Basic Sciences
 > Central University of Tamil Nadu
 > Thiruvarur
 > Tamil Nadu - 610101
 > Ph no - +91-8675834507
 >
 > ___
 > Wien mailing list
 > Wien@zeus.theochem.tuwien.ac.at
 > http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
 > SEARCH the MAILING-LIST at:
 http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html
 >
 >
 > ___
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 > http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
 > SEARCH the MAILING-LIST at:
 http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html

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>>>
>>>
>>>
>>> --
>>> Lokanath Patra
>>> Ph.D Scholar
>>> Dept. of Physics
>>> School of Applied and Basic Sciences
>>> Central University of Tamil Nadu
>>> Thiruvarur
>>> Tamil Nadu - 610101
>>> Ph no - +91-8675834507
>>>
>>> ___
>>> Wien mailing list
>>> Wien@zeus.theochem.tuwien.ac.at
>>> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
>>> SEARCH the MAILING-LIST at:
>>> http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html
>>>
>>>
>>
>> ___
>> Wien mailing list
>> Wien@zeus.theochem.tuwien.ac.at
>> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
>> SEARCH the MAILING-LIST at:
>> http://www.mail-archive.com/wien@zeus.theoc

Re: [Wien] force difference between LAPW and PAW method

[Peter Blaha]

This looks fairly large.

I do NOT understand your statement of using "the same RKMAX" ???
PAW does not have RKMAX and their KMAX has NOTHING to do with ours.
What was your RKMAX and what are youre sphere sizes ???

k-mesh: not only the grid is important ! As far as I know, VASP usually 
uses a "huge" temperature broadening. What FERMI-method are you using ?


spin-polarization ??

Is the PAW done with VASP and a fairly new release (accurate PAW 
potentials ?)


On 01/29/2016 10:50 AM, Pavel Ondračka wrote:

Dear Wien2k mailing list,

I've been doing some calculation on a moderately large (around 100
atoms) amorphous-like SixTi1-xO2 cells produced by simulated annealing
MD in a PAW software. According to my colleague who did the final force
relaxation, the residual forces on atoms should be around 0.5
mRyd/Bohr. However when I calculate forces in Wien2k I see forces of
order of magnitude larger, eg. some as large as 30mRyd/Bohr.

This are exactly the same calculations: both using PBE, same k-grid,
same RKMAX (calculated from cutoff using the formula from UG) and I've
spent a lot of time checking the force convergence with respect to all
possible parameters.

We did some tests with small cells (eg. 10 atoms) and there we can get
a consistent results with max difference of forces around 10-20% which
I find reasonable. I'm actually quite clueless about it. I've been
suspecting user error at the beginning however I haven't found any so
far. My current theory is that in this large cases without symmetry
maybe the small differences between methods somehow sum up and hence
the big difference in final forces, however I would like to hear your
opinion in this matter.

Best regards
Pavel Ondračka
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--

  P.Blaha
--
Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
Phone: +43-1-58801-165300 FAX: +43-1-58801-165982
Email: bl...@theochem.tuwien.ac.atWIEN2k: http://www.wien2k.at
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Re: [Wien] force difference between LAPW and PAW method

[Pavel Ondračka]

Laurence Marks píše v Pá 29. 01. 2016 v 04:22 -0600:
> Did you check for lattice parameter changes? A relatively small
> change for a single unit cell can translate to something larger.
> Unfortunately you need a reference compound, which is not so simple
> in your case. Perhaps test SiO2, TiO2 & a few simple similar
> compounds with the PAW & Wien2k.

Yeah, some difference in cell size or positions was one of my suspects.
I usually use VESTA to read the structure file from PAW software, then
output to cif and use cif2struct to convert to struct and I was
suspecting that maybe somewhere in this process I lose precision. 
So I've actually written a small python script to convert it directly
with full precision allowed by the struct format, however the result
were almost identical.
Regarding the test cases, we tested eg. with rutile (with one atom
slightly displaced to induce some forces) and the result were
comparable (few percent difference).

Best regards
Pavel Ondračka
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Re: [Wien] BerryPi

[lokanath patra]

Dear Fecher and Bhamu,
I also think that the error is due to the symmetry after changing the
struct file. But the tutorial says ''Do not rerun the init_lapw as it may
realize a higher symmetry. The intention is to keep symmetry unchanged
between subsequent runs''. Just check the 3rd and 4 points of the link.
https://github.com/spichardo/BerryPI/wiki/Tutorial-3:-Non-orthogonal-lattice-vectors

Thanks.


On Fri, Jan 29, 2016 at 2:47 PM, Dr. K. C. Bhamu 
wrote:

> Hello Lokanath
> I did a mistake in my previous mail regarding rmt issue.
> Your RMT is ok (I did a mistack in compilation).
>
> your *x nn* gives error so definitely something is wrong with struct file.
>
>
> *Experts may help you.*
> regards
> Bhamu
>
>
>
>
>
> On Fri, Jan 29, 2016 at 11:19 AM, lokanath patra <
> lokanath.patra...@gmail.com> wrote:
>
>> Dear Dr Bhamu,
>> Actually I have already searched for that. But as  I am changing the
>> position of an atom, I guess the symmetry breaks and the error comes. With
>> the struct file with unchanged atomic position, it runs fine.
>>
>> Dear Oleg Rubel,
>>
>> Here I am attaching the two struct files used in “initial” calculation
>> and after the displacement is introduced.
>>
>> Thanks.
>>
>> On Thu, Jan 28, 2016 at 11:29 PM, Oleg Rubel  wrote:
>>
>>> Would it be possible to attach the structure files used in “initial”
>>> calculation and after the displacement is introduced?
>>>
>>> Thank you
>>> Oleg
>>>
>>> > On Jan 28, 2016, at 11:08, Dr. K. C. Bhamu 
>>> wrote:
>>> >
>>> > Dear Lokanath
>>> >
>>> > Your error is wellknown if you search mailing list.
>>> > You may try :
>>> https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg08405.html
>>> >
>>> > Some time ago I got same error and by compiling SRC_hf agin I overcome
>>> the error.
>>> >
>>> > regards
>>> >
>>> >
>>> >
>>> > 
>>> > Dr. K. C. Bhamu
>>> > (UGC-Dr. D. S. Kothari Postdoc Fellow)
>>> > Department of Physics
>>> > Goa University, Goa-403 206
>>> > India
>>> > Mob. No.  +91-9782911977
>>> >
>>> > On Thu, Jan 28, 2016 at 8:33 PM, lokanath patra <
>>> lokanath.patra...@gmail.com> wrote:
>>> > Dear Users,
>>> >
>>> > I am trying to calculate born effective charge for Bi atom in BiFeO3.
>>> I followed the tutorial for GaAs as BiFeO3 is having non orthogonal lattice
>>> vectors. I used berrypi with -s option as it consists of magnetic ion. But
>>> after changing the position of Bi atom by 0.001, when I put the command ''x
>>> dstart'' to initialize the electron density, it is showing 'rot-def' error.
>>> Please help.
>>> >
>>> > Thanks in advance.
>>> >
>>> > --
>>> > Lokanath Patra
>>> > Ph.D Scholar
>>> > Dept. of Physics
>>> > School of Applied and Basic Sciences
>>> > Central University of Tamil Nadu
>>> > Thiruvarur
>>> > Tamil Nadu - 610101
>>> > Ph no - +91-8675834507
>>> >
>>> > ___
>>> > Wien mailing list
>>> > Wien@zeus.theochem.tuwien.ac.at
>>> > http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
>>> > SEARCH the MAILING-LIST at:
>>> http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html
>>> >
>>> >
>>> > ___
>>> > Wien mailing list
>>> > Wien@zeus.theochem.tuwien.ac.at
>>> > http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
>>> > SEARCH the MAILING-LIST at:
>>> http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html
>>>
>>> ___
>>> Wien mailing list
>>> Wien@zeus.theochem.tuwien.ac.at
>>> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
>>> SEARCH the MAILING-LIST at:
>>> http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html
>>>
>>
>>
>>
>> --
>> Lokanath Patra
>> Ph.D Scholar
>> Dept. of Physics
>> School of Applied and Basic Sciences
>> Central University of Tamil Nadu
>> Thiruvarur
>> Tamil Nadu - 610101
>> Ph no - +91-8675834507
>>
>> ___
>> Wien mailing list
>> Wien@zeus.theochem.tuwien.ac.at
>> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
>> SEARCH the MAILING-LIST at:
>> http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html
>>
>>
>
> ___
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> SEARCH the MAILING-LIST at:
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>
>


-- 
Lokanath Patra
Ph.D Scholar
Dept. of Physics
School of Applied and Basic Sciences
Central University of Tamil Nadu
Thiruvarur
Tamil Nadu - 610101
Ph no - +91-8675834507
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[Wien] Need your help

[sikander Azam]

Dear All
Can we calculate Poloran in wien2k? if yes, please guide me how to
calculate it.
Regards
Sikander
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Re: [Wien] force difference between LAPW and PAW method

[Laurence Marks]

Did you check for lattice parameter changes? A relatively small change for
a single unit cell can translate to something larger. Unfortunately you
need a reference compound, which is not so simple in your case. Perhaps
test SiO2, TiO2 & a few simple similar compounds with the PAW & Wien2k.

---
Professor Laurence Marks
Department of Materials Science and Engineering
Northwestern University
http://www.numis.northwestern.edu
Corrosion in 4D http://MURI4D.numis.northwestern.edu
Co-Editor, Acta Cryst A
"Research is to see what everybody else has seen, and to think what nobody
else has thought"
Albert Szent-Gyorgi
On Jan 29, 2016 03:50, "Pavel Ondračka"  wrote:

> Dear Wien2k mailing list,
>
> I've been doing some calculation on a moderately large (around 100
> atoms) amorphous-like SixTi1-xO2 cells produced by simulated annealing
> MD in a PAW software. According to my colleague who did the final force
> relaxation, the residual forces on atoms should be around 0.5
> mRyd/Bohr. However when I calculate forces in Wien2k I see forces of
> order of magnitude larger, eg. some as large as 30mRyd/Bohr.
>
> This are exactly the same calculations: both using PBE, same k-grid,
> same RKMAX (calculated from cutoff using the formula from UG) and I've
> spent a lot of time checking the force convergence with respect to all
> possible parameters.
>
> We did some tests with small cells (eg. 10 atoms) and there we can get
> a consistent results with max difference of forces around 10-20% which
> I find reasonable. I'm actually quite clueless about it. I've been
> suspecting user error at the beginning however I haven't found any so
> far. My current theory is that in this large cases without symmetry
> maybe the small differences between methods somehow sum up and hence
> the big difference in final forces, however I would like to hear your
> opinion in this matter.
>
> Best regards
> Pavel Ondračka
> ___
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[Wien] force difference between LAPW and PAW method

[Pavel Ondračka]

Dear Wien2k mailing list,

I've been doing some calculation on a moderately large (around 100
atoms) amorphous-like SixTi1-xO2 cells produced by simulated annealing
MD in a PAW software. According to my colleague who did the final force
relaxation, the residual forces on atoms should be around 0.5
mRyd/Bohr. However when I calculate forces in Wien2k I see forces of
order of magnitude larger, eg. some as large as 30mRyd/Bohr.

This are exactly the same calculations: both using PBE, same k-grid,
same RKMAX (calculated from cutoff using the formula from UG) and I've
spent a lot of time checking the force convergence with respect to all
possible parameters.

We did some tests with small cells (eg. 10 atoms) and there we can get
a consistent results with max difference of forces around 10-20% which
I find reasonable. I'm actually quite clueless about it. I've been
suspecting user error at the beginning however I haven't found any so
far. My current theory is that in this large cases without symmetry
maybe the small differences between methods somehow sum up and hence
the big difference in final forces, however I would like to hear your
opinion in this matter.

Best regards
Pavel Ondračka
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Re: [Wien] BerryPi

[Dr. K. C. Bhamu]

Hello Lokanath
I did a mistake in my previous mail regarding rmt issue.
Your RMT is ok (I did a mistack in compilation).

your *x nn* gives error so definitely something is wrong with struct file.


*Experts may help you.*
regards
Bhamu




On Fri, Jan 29, 2016 at 11:19 AM, lokanath patra <
lokanath.patra...@gmail.com> wrote:

> Dear Dr Bhamu,
> Actually I have already searched for that. But as  I am changing the
> position of an atom, I guess the symmetry breaks and the error comes. With
> the struct file with unchanged atomic position, it runs fine.
>
> Dear Oleg Rubel,
>
> Here I am attaching the two struct files used in “initial” calculation and
> after the displacement is introduced.
>
> Thanks.
>
> On Thu, Jan 28, 2016 at 11:29 PM, Oleg Rubel  wrote:
>
>> Would it be possible to attach the structure files used in “initial”
>> calculation and after the displacement is introduced?
>>
>> Thank you
>> Oleg
>>
>> > On Jan 28, 2016, at 11:08, Dr. K. C. Bhamu  wrote:
>> >
>> > Dear Lokanath
>> >
>> > Your error is wellknown if you search mailing list.
>> > You may try :
>> https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg08405.html
>> >
>> > Some time ago I got same error and by compiling SRC_hf agin I overcome
>> the error.
>> >
>> > regards
>> >
>> >
>> >
>> > 
>> > Dr. K. C. Bhamu
>> > (UGC-Dr. D. S. Kothari Postdoc Fellow)
>> > Department of Physics
>> > Goa University, Goa-403 206
>> > India
>> > Mob. No.  +91-9782911977
>> >
>> > On Thu, Jan 28, 2016 at 8:33 PM, lokanath patra <
>> lokanath.patra...@gmail.com> wrote:
>> > Dear Users,
>> >
>> > I am trying to calculate born effective charge for Bi atom in BiFeO3. I
>> followed the tutorial for GaAs as BiFeO3 is having non orthogonal lattice
>> vectors. I used berrypi with -s option as it consists of magnetic ion. But
>> after changing the position of Bi atom by 0.001, when I put the command ''x
>> dstart'' to initialize the electron density, it is showing 'rot-def' error.
>> Please help.
>> >
>> > Thanks in advance.
>> >
>> > --
>> > Lokanath Patra
>> > Ph.D Scholar
>> > Dept. of Physics
>> > School of Applied and Basic Sciences
>> > Central University of Tamil Nadu
>> > Thiruvarur
>> > Tamil Nadu - 610101
>> > Ph no - +91-8675834507
>> >
>> > ___
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>> > SEARCH the MAILING-LIST at:
>> http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html
>> >
>> >
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>> http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html
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>
>
>
> --
> Lokanath Patra
> Ph.D Scholar
> Dept. of Physics
> School of Applied and Basic Sciences
> Central University of Tamil Nadu
> Thiruvarur
> Tamil Nadu - 610101
> Ph no - +91-8675834507
>
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Re: [Wien] BerryPi

[Fecher, Gerhard]

Did you change only the position ? That might be the cause of your troubles.
you also need to have the correct symmetry (space group) for the new structure 
! 

Ciao
Gerhard

DEEP THOUGHT in D. Adams; Hitchhikers Guide to the Galaxy:
"I think the problem, to be quite honest with you,
is that you have never actually known what the question is."


Dr. Gerhard H. Fecher
Institut of Inorganic and Analytical Chemistry
Johannes Gutenberg - University
55099 Mainz
and
Max Planck Institute for Chemical Physics of Solids
01187 Dresden

Von: wien-boun...@zeus.theochem.tuwien.ac.at 
[wien-boun...@zeus.theochem.tuwien.ac.at] im Auftrag von lokanath patra 
[lokanath.patra...@gmail.com]
Gesendet: Freitag, 29. Januar 2016 08:39
An: A Mailing list for WIEN2k users
Betreff: Re: [Wien] BerryPi

I just followed the tutorial of Born effective charge. According to that, we 
have to initialize the calculation for the unchanged material. Then we have to 
change the position and den we have to initialize the electron density only 
i.e. ''x dstart''. They have mentioned not to rerun init_lapw . So I 
initialized only the electron density and got the error.

Thanks.

On Fri, Jan 29, 2016 at 12:13 PM, Dr. K. C. Bhamu 
mailto:kcbham...@gmail.com>> wrote:
One more thing: I dont know how to calculate born effective charge. But you see 
your new struct file there are 6 position for Bi, 6 position for O and 2 for 
Fe. So new composition is 3:1:3 while in original it is 1:1:3.

So look on the new struct file, how you changing position of Bi and why rmt get 
reduced.

regards
Bhamu




On Fri, Jan 29, 2016 at 11:19 AM, lokanath patra 
mailto:lokanath.patra...@gmail.com>> wrote:
Dear Dr Bhamu,
Actually I have already searched for that. But as  I am changing the position 
of an atom, I guess the symmetry breaks and the error comes. With the struct 
file with unchanged atomic position, it runs fine.

Dear Oleg Rubel,

Here I am attaching the two struct files used in “initial” calculation and 
after the displacement is introduced.

Thanks.

On Thu, Jan 28, 2016 at 11:29 PM, Oleg Rubel 
mailto:oru...@lakeheadu.ca>> wrote:
Would it be possible to attach the structure files used in “initial” 
calculation and after the displacement is introduced?

Thank you
Oleg

> On Jan 28, 2016, at 11:08, Dr. K. C. Bhamu 
> mailto:kcbham...@gmail.com>> wrote:
>
> Dear Lokanath
>
> Your error is wellknown if you search mailing list.
> You may try : 
> https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg08405.html
>
> Some time ago I got same error and by compiling SRC_hf agin I overcome the 
> error.
>
> regards
>
>
>
> 
> Dr. K. C. Bhamu
> (UGC-Dr. D. S. Kothari Postdoc Fellow)
> Department of Physics
> Goa University, Goa-403 206
> India
> Mob. No.  +91-9782911977
>
> On Thu, Jan 28, 2016 at 8:33 PM, lokanath patra 
> mailto:lokanath.patra...@gmail.com>> wrote:
> Dear Users,
>
> I am trying to calculate born effective charge for Bi atom in BiFeO3. I 
> followed the tutorial for GaAs as BiFeO3 is having non orthogonal lattice 
> vectors. I used berrypi with -s option as it consists of magnetic ion. But 
> after changing the position of Bi atom by 0.001, when I put the command ''x 
> dstart'' to initialize the electron density, it is showing 'rot-def' error. 
> Please help.
>
> Thanks in advance.
>
> --
> Lokanath Patra
> Ph.D Scholar
> Dept. of Physics
> School of Applied and Basic Sciences
> Central University of Tamil Nadu
> Thiruvarur
> Tamil Nadu - 610101
> Ph no - +91-8675834507
>
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>
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--
Lokanath Patra
Ph.D Scholar
Dept. of Physics
School of Applied and Basic Sciences
Central University of Tamil Nadu
Thiruvarur
Tamil Nadu - 610101
Ph no - +91-8675834507

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