Re: [Wien] Change of structure symmetry

2016-10-15 Thread delamora
Dear Tomas

Are you a hokey player? I suppose not!

The problem with this is that the cell goes from CXY to P then in the cell the 
number of atoms doubles.

What I did is to see the positions of the changes of the atoms with sgroup

Before sgroup:

 1: X=0.5000 Y=0. Z=0.6300
 2: X=0. Y=0. Z=0.6300
 3: X=0.5000 Y=0.2500 Z=0.38122315
 3: X=0.5000 Y=0.7500 Z=0.38122315
 4: X=0.5000 Y=0.2500 Z=0.87877685
 4: X=0.5000 Y=0.7500 Z=0.87877685
 5: X=0.7500 Y=0. Z=0.35739347
 5: X=0.2500 Y=0. Z=0.35739347


16: X=0.5000 Y=0.7500 Z=0.73290499
17: X=0.2500 Y=0.34304549 Z=0.35413297
17: X=0.7500 Y=0.65695451 Z=0.35413297
17: X=0.7500 Y=0.34304549 Z=0.35413297
17: X=0.2500 Y=0.65695451 Z=0.35413297
18: X=0.7500 Y=0.15695450 Z=0.90586703
=

After sgroup

 1: X=0.6300 Y=0.6300 Z=0.5000
 2: X=0.6300 Y=0.6300 Z=0.
 3: X=0.63122315 Y=0.38122315 Z=0.
 4: X=0.63122315 Y=0.38122315 Z=0.5000
 5: X=0.12877685 Y=0.87877685 Z=0.
 6: X=0.12877685 Y=0.87877685 Z=0.5000
 7: X=0.35739347 Y=0.35739347 Z=0.2500
 7:X= 0.35739347 Y=0.35739347 Z=0.7500
.

20: X=0.98290499 Y=0.73290499 Z=0.5000
21: X=0.51108748 Y=0.35413297 Z=0.2500
21:X= 0.51108748 Y=0.35413297 Z=0.7500
22: X=0.69717846 Y=0.35413297 Z=0.2500
22:X= 0.69717846 Y=0.35413297 Z=0.7500
23: X=0.74891253 Y=0.90586703 Z=0.2500


As you can see

a=>c

b+c=>a

c=>b

then you can see how the atoms split, for example

atoms '3' split into '3' and '4'

atoms '17' split into '21' and '22'

one have to take into account that the original structure is

CXY and a,b are equivalent to a+.5,b+.5


The b+c=>a is the consequence of the 90 => 135 degrees


I would be easy to make a program to change 135 => 90


Thank for your comments


 Pablo


De: Wien <wien-boun...@zeus.theochem.tuwien.ac.at> en nombre de Tomas Kana 
<k...@seznam.cz>
Enviado: viernes, 14 de octubre de 2016 05:24:55 a. m.
Para: A Mailing list for WIEN2k users
Asunto: Re: [Wien] Change of structure symmetry

Dear Pablo,
I tried to play with your structure and I succeeded.
First,  run
x supercell
always one cell in x- y- and z- directions
zero shift in all directions
 Enter your  target lattice type:
P
(you must choose primitive lattice in order to break
the symmetries you do not want there).
Zero vacuum in all directions.
Then
cp TiO2-sup_super.struct TiO2-sup.struct
Edit the TiO2-sup.struct file and find the two Cu atoms.
Rewrite the space after first Cu to 1.
Rewrite the space after second Cu to 2.
Or do these two things comfortably using w2web.
You must have them inequivalent.
By the way, are you sure that the vacuum you have for your slab is
sufficient? When I use slabs I try to have vacuum around 20 bohrs.
Then  run
x sgroup
By checking TiO2-sup.outputsgroup you see that sgroup has chosen
monoclinic lattice but with all three angles equal to 90 degrees.
(Space group 56  6 Pm)
Then, I STRONGLY RECOMMEND TO ERASE ONE OF THE Cu ATOMS,
probably the one at the position 0 0 0.
It worked on my computer.
HTH
Tomas
___
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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


Re: [Wien] Change of structure symmetry attaching the "fine" structure file

2016-10-14 Thread Tomas Kana
Dear Pablo,
I attach the "fine" structure file TiO2-sup.struct_sgroup
I again recommend to erase (rather by using w2web 
if you are not perfectly familiar with the formatting) 
the Cu1  atom located at 0 0 0. 
Best  regards 
Tomas 

P   LATTICE,NONEQUIV.ATOMS: 56 6 Pm
MODE OF CALC=RELA unit=bohr
 23.838706 23.838290 11.187184 90.00 90.00 90.00
ATOM   1: X=0. Y=0.6300 Z=0.5000
  MULT= 1  ISPLIT= 8
Ti1NPT=  781  R0=0.5000 RMT=1.7900   Z: 22.0
LOCAL ROT MATRIX:1.000 0.000 0.000
 0.000 1.000 0.000
 0.000 0.000 1.000
ATOM   2: X=0.5000 Y=0.6300 Z=0.
  MULT= 1  ISPLIT= 8
Ti2NPT=  781  R0=0.5000 RMT=1.7900   Z: 22.0
LOCAL ROT MATRIX:1.000 0.000 0.000
 0.000 1.000 0.000
 0.000 0.000 1.000
ATOM   3: X=0. Y=0.6300 Z=0.
  MULT= 1  ISPLIT= 8
Ti3NPT=  781  R0=0.5000 RMT=1.7900   Z: 22.0
LOCAL ROT MATRIX:1.000 0.000 0.000
 0.000 1.000 0.000
 0.000 0.000 1.000
ATOM   4: X=0.5000 Y=0.6300 Z=0.5000
  MULT= 1  ISPLIT= 8
Ti4NPT=  781  R0=0.5000 RMT=1.7900   Z: 22.0
LOCAL ROT MATRIX:1.000 0.000 0.000
 0.000 1.000 0.000
 0.000 0.000 1.000
ATOM   5: X=0.7500 Y=0.38122315 Z=0.5000
  MULT= 1  ISPLIT= 8
Ti5NPT=  781  R0=0.5000 RMT=1.7900   Z: 22.0
LOCAL ROT MATRIX:1.000 0.000 0.000
 0.000 1.000 0.000
 0.000 0.000 1.000
ATOM   6: X=0.2500 Y=0.38122315 Z=0.5000
  MULT= 1  ISPLIT= 8
Ti6NPT=  781  R0=0.5000 RMT=1.7900   Z: 22.0
LOCAL ROT MATRIX:1.000 0.000 0.000
 0.000 1.000 0.000
 0.000 0.000 1.000
ATOM   7: X=0.2500 Y=0.38122315 Z=0.
  MULT= 1  ISPLIT= 8
Ti7NPT=  781  R0=0.5000 RMT=1.7900   Z: 22.0
LOCAL ROT MATRIX:1.000 0.000 0.000
 0.000 1.000 0.000
 0.000 0.000 1.000
ATOM   8: X=0.7500 Y=0.38122315 Z=0.
  MULT= 1  ISPLIT= 8
Ti8NPT=  781  R0=0.5000 RMT=1.7900   Z: 22.0
LOCAL ROT MATRIX:1.000 0.000 0.000
 0.000 1.000 0.000
 0.000 0.000 1.000
ATOM   9: X=0.7500 Y=0.87877685 Z=0.5000
  MULT= 1  ISPLIT= 8
Ti9NPT=  781  R0=0.5000 RMT=1.7900   Z: 22.0
LOCAL ROT MATRIX:1.000 0.000 0.000
 0.000 1.000 0.000
 0.000 0.000 1.000
ATOM  10: X=0.2500 Y=0.87877685 Z=0.5000
  MULT= 1  ISPLIT= 8
Ti10   NPT=  781  R0=0.5000 RMT=1.7900   Z: 22.0
LOCAL ROT MATRIX:1.000 0.000 0.000
 0.000 1.000 0.000
 0.000 0.000 1.000
ATOM  11: X=0.2500 Y=0.87877685 Z=0.
  MULT= 1  ISPLIT= 8
Ti11   NPT=  781  R0=0.5000 RMT=1.7900   Z: 22.0
LOCAL ROT MATRIX:1.000 0.000 0.000
 0.000 1.000 0.000
 0.000 0.000 1.000
ATOM  12: X=0.7500 Y=0.87877685 Z=0.
  MULT= 1  ISPLIT= 8
Ti12   NPT=  781  R0=0.5000 RMT=1.7900   Z: 22.0
LOCAL ROT MATRIX:1.000 0.000 0.000
 0.000 1.000 0.000
 0.000 0.000 1.000
ATOM  13: X=0. Y=0.35739347 Z=0.2500
  MULT= 2  ISPLIT= 8
  13: X=0. Y=0.35739347 Z=0.7500
Ti13   NPT=  781  R0=0.5000 RMT=1.7900   Z: 22.0
LOCAL ROT MATRIX:1.000 0.000 0.000
 0.000 1.000 0.000
 0.000 0.000 1.000
ATOM  14: X=0.5000 Y=0.35739347 Z=0.7500
  MULT= 2  ISPLIT= 8
  14: X=0.5000 Y=0.35739347 Z=0.2500
Ti14   NPT=  781  R0=0.5000 RMT=1.7900   Z: 22.0
LOCAL ROT MATRIX:1.000 0.000 0.000
 0.000 1.000 0.000
 0.000 0.000 1.000
ATOM  15: X=0. Y=0.90260653 Z=0.2500
  MULT= 2  ISPLIT= 8
  15: X=0. Y=0.90260653 Z=0.7500
Ti15   NPT=  781  R0=0.5000 RMT=1.7900   Z: 22.0
LOCAL ROT MATRIX:1.000 0.000 0.000

Re: [Wien] Change of structure symmetry

2016-10-14 Thread Tomas Kana
Dear Pablo, 
I tried to play with your structure and I succeeded. 
First,  run 
x supercell 
always one cell in x- y- and z- directions 
zero shift in all directions 
 Enter your  target lattice type:
P 
(you must choose primitive lattice in order to break 
the symmetries you do not want there). 
Zero vacuum in all directions. 
Then 
cp TiO2-sup_super.struct TiO2-sup.struct 
Edit the TiO2-sup.struct file and find the two Cu atoms. 
Rewrite the space after first Cu to 1. 
Rewrite the space after second Cu to 2. 
Or do these two things comfortably using w2web. 
You must have them inequivalent. 
By the way, are you sure that the vacuum you have for your slab is 
sufficient? When I use slabs I try to have vacuum around 20 bohrs. 
Then  run 
x sgroup 
By checking TiO2-sup.outputsgroup you see that sgroup has chosen 
monoclinic lattice but with all three angles equal to 90 degrees. 
(Space group 56  6 Pm) 
Then, I STRONGLY RECOMMEND TO ERASE ONE OF THE Cu ATOMS, 
probably the one at the position 0 0 0. 
It worked on my computer. 
HTH 
Tomas 
___
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


Re: [Wien] Change of structure symmetry

2016-10-13 Thread delamora
Thanks, I tried but it did not work for this case


De: Wien <wien-boun...@zeus.theochem.tuwien.ac.at> en nombre de Laurence Marks 
<laurence.ma...@gmail.com>
Enviado: jueves, 13 de octubre de 2016 07:35:42 a. m.
Para: A Mailing list for WIEN2k users
Asunto: Re: [Wien] Change of structure symmetry


Sometimes changing the 90 to 92 before sgroup, then changing it back works. To 
be used with extreme care.

---
Professor Laurence Marks
"Research is to see what everybody else has seen, and to think what nobody else 
has thought", Albert Szent-Gyorgi
http://www.numis.northwestern.edu
Corrosion in 4D http://MURI4D.numis.northwestern.edu
Partner of the CFW 100% gender equity project, 
www.cfw.org/100-percent<http://www.cfw.org/100-percent>
Co-Editor, Acta Cryst A


On Oct 12, 2016 17:36, "delamora" <delam...@unam.mx<mailto:delam...@unam.mx>> 
wrote:

Thank you for all your comments.

Two more comments;

Here is the cell with the orthorhombic symmetry, 90 degree angles, which I 
think is correct

sgroup does not accept it and changes one angle to; 135.000500, with the 
corresponding arrangements of atoms

With this new structure XCrySDen gives an error

but if I change this angle by little: 135.00 or 136.00 then I can see it 
with XCrySDen


This is not the first time that these two problems happen


Now I am running with the unchanged, orthorhombic, cell no error seems to 
appear as long as I ignore sgroup


De: Wien 
<wien-boun...@zeus.theochem.tuwien.ac.at<mailto:wien-boun...@zeus.theochem.tuwien.ac.at>>
 en nombre de JUAN MANUEL PEREZ <jm.perez-m...@ehu.eus>
Enviado: miércoles, 12 de octubre de 2016 12:37:11 p. m.
Para: A Mailing list for WIEN2k users
Asunto: Re: [Wien] Change of structure symmetry


C11m does not exist. It includes a gratuit centering that can be
elliminated by changing the unit cell within the same convention (one unit
cell direction perpendicular to the mirror plane).

But, as said in the previous message,  the symmetry of the discussed
structure keeping the original unit cell would be given rather by the label
Cm11 with the monoclinic axis along a (the alpha angle may be different
from 90 but it is not forced to be different!),  and therefore it does not
correspond to none of the two possible standard settings (monoclinic axis
along b or c) that you have in the Wikipedia.

In any case, it is true that sgroup does not propose the more reasonable
unit cell among those possible in
the standard description of the symmetry as C1m1, and coud have just
interchanged the axes, keeping the three 90 degrees angles. BUT the
identification of symmetries is an algebraic problem where the specific
metrics of the unit cell does not play a role, and all this type of
programs do not care about it. To find the “nicest” unit cell among the
possible ones is beyond them, and if one wants to consider all the possible
cases that one can encounter this unit cell “embellishment process is not
trivial. The best is to identify the “normalizer” of the space group in
the listings available (see for instance the Bilbao server), which defines
the unit cell changes that are possible, and find by hand the one with with
which we are happy.

best regards,

J. Manuel Perez-Mato
Fac. Ciencia y Tecnologia,
Universidad del Pais Vasco, UPV
48080 BILBAO,
Spain

***

> El 12/10/2016, a las 17:51, Laurence Marks 
> <l-ma...@northwestern.edu<mailto:l-ma...@northwestern.edu>>
> escribió:
>
> I meant "correct" when the cell is C11m, which is better for Wien.
>
> On Wed, Oct 12, 2016 at 10:50 AM, Laurence Marks
> <l-ma...@northwestern.edu<mailto:l-ma...@northwestern.edu>> wrote:
>
>> My two cents worth. If you look at, for
>> instance, 
>> https://en.wikipedia.org/wiki/List_of_space_groups<https://urldefense.proofpoint.com/v2/url?u=https-3A__en.wikipedia.org_wiki_List-5Fof-5Fspace-5Fgroups=CwMF-g=yHlS04HhBraes5BQ9ueu5zKhE7rtNXt_d012z2PA6ws=U_T4PL6jwANfAy4rnxTj8IUxm818jnvqKFdqWLwmqg0=x89rhJoaNoZvL4TggKrrel0P3TQIcL6QF7ROlB8oyzs=UjRf_fqc-qYdKi9V79WaiW2VQM-j_J6jHqrY-a3nlLA=>,
>>  Cm #8 is
>> a monoclinic spacegroup which (in the B11m setting) has beta .ne. 90.
>> It is "correct" to have gamma .ne. 90 for the standard convention.
>> However, this is inconvenient and it would be nice if sgroup made an
>> exception for Wien.
>>
>> On Wed, Oct 12, 2016 at 10:14 AM, Peter Blaha
>> <pbl...@theochem.tuwien.ac.at<mailto:pbl...@theochem.tuwien.ac.at>> wrote:
>>
>>> ===
>>>
>>> The structure that you have attached does NOT have Cmm2 as space group
>>> symmetry, but only Cm, which is the one that sgroup correctl

Re: [Wien] Change of structure symmetry

2016-10-13 Thread Laurence Marks
Sometimes changing the 90 to 92 before sgroup, then changing it back works.
To be used with extreme care.

---
Professor Laurence Marks
"Research is to see what everybody else has seen, and to think what nobody
else has thought", Albert Szent-Gyorgi
http://www.numis.northwestern.edu
Corrosion in 4D http://MURI4D.numis.northwestern.edu
Partner of the CFW 100% gender equity project, www.cfw.org/100-percent
Co-Editor, Acta Cryst A


On Oct 12, 2016 17:36, "delamora" <delam...@unam.mx> wrote:

> Thank you for all your comments.
>
> Two more comments;
>
> Here is the cell with the orthorhombic symmetry, 90 degree angles, which
> I think is correct
>
> sgroup does not accept it and changes one angle to; 135.000500, with the
> corresponding arrangements of atoms
>
> With this new structure XCrySDen gives an error
>
> but if I change this angle by little: 135.00 or 136.00 then I can see
> it with XCrySDen
>
>
> This is not the first time that these two problems happen
>
>
> Now I am running with the unchanged, orthorhombic, cell no error seems to
> appear as long as I ignore sgroup
> --
> *De:* Wien <wien-boun...@zeus.theochem.tuwien.ac.at> en nombre de JUAN
> MANUEL PEREZ <jm.perez-m...@ehu.eus>
> *Enviado:* miércoles, 12 de octubre de 2016 12:37:11 p. m.
> *Para:* A Mailing list for WIEN2k users
> *Asunto:* Re: [Wien] Change of structure symmetry
>
>
> C11m does not exist. It includes a gratuit centering that can be
> elliminated by changing the unit cell within the same convention (one unit
> cell direction perpendicular to the mirror plane).
>
> But, as said in the previous message,  the symmetry of the discussed
> structure keeping the original unit cell would be given rather by the label
> Cm11 with the monoclinic axis along a (the alpha angle may be different
> from 90 but it is not forced to be different!),  and therefore it does not
> correspond to none of the two possible standard settings (monoclinic axis
> along b or c) that you have in the Wikipedia.
>
> In any case, it is true that sgroup does not propose the more reasonable
> unit cell among those possible in
> the standard description of the symmetry as C1m1, and coud have just
> interchanged the axes, keeping the three 90 degrees angles. BUT the
> identification of symmetries is an algebraic problem where the specific
> metrics of the unit cell does not play a role, and all this type of
> programs do not care about it. To find the “nicest” unit cell among the
> possible ones is beyond them, and if one wants to consider all the possible
> cases that one can encounter this unit cell “embellishment process is not
> trivial. The best is to identify the “normalizer” of the space group in
> the listings available (see for instance the Bilbao server), which defines
> the unit cell changes that are possible, and find by hand the one with with
> which we are happy.
>
> best regards,
>
> J. Manuel Perez-Mato
> Fac. Ciencia y Tecnologia,
> Universidad del Pais Vasco, UPV
> 48080 BILBAO,
> Spain
>
> ***
>
> > El 12/10/2016, a las 17:51, Laurence Marks <l-ma...@northwestern.edu>
> > escribió:
> >
> > I meant "correct" when the cell is C11m, which is better for Wien.
> >
> > On Wed, Oct 12, 2016 at 10:50 AM, Laurence Marks
> > <l-ma...@northwestern.edu> wrote:
> >
> >> My two cents worth. If you look at, for
> >> instance, https://en.wikipedia.org/wiki/List_of_space_groups
> <https://urldefense.proofpoint.com/v2/url?u=https-3A__en.wikipedia.org_wiki_List-5Fof-5Fspace-5Fgroups=CwMF-g=yHlS04HhBraes5BQ9ueu5zKhE7rtNXt_d012z2PA6ws=U_T4PL6jwANfAy4rnxTj8IUxm818jnvqKFdqWLwmqg0=x89rhJoaNoZvL4TggKrrel0P3TQIcL6QF7ROlB8oyzs=UjRf_fqc-qYdKi9V79WaiW2VQM-j_J6jHqrY-a3nlLA=>,
> Cm #8 is
> >> a monoclinic spacegroup which (in the B11m setting) has beta .ne. 90.
> >> It is "correct" to have gamma .ne. 90 for the standard convention.
> >> However, this is inconvenient and it would be nice if sgroup made an
> >> exception for Wien.
> >>
> >> On Wed, Oct 12, 2016 at 10:14 AM, Peter Blaha
> >> <pbl...@theochem.tuwien.ac.at> wrote:
> >>
> >>> ===
> >>>
> >>> The structure that you have attached does NOT have Cmm2 as space group
> >>> symmetry, but only Cm, which is the one that sgroup correctly finds.
> The
> >>> mirror plane of the Cm group is perpendicular to the original a axis,
> >>> and
> >>> in the standard description of Cm it should be pe

Re: [Wien] Change of structure symmetry

2016-10-12 Thread delamora
Thank you for all your comments.

Two more comments;

Here is the cell with the orthorhombic symmetry, 90 degree angles, which I 
think is correct

sgroup does not accept it and changes one angle to; 135.000500, with the 
corresponding arrangements of atoms

With this new structure XCrySDen gives an error

but if I change this angle by little: 135.00 or 136.00 then I can see it 
with XCrySDen


This is not the first time that these two problems happen


Now I am running with the unchanged, orthorhombic, cell no error seems to 
appear as long as I ignore sgroup


De: Wien <wien-boun...@zeus.theochem.tuwien.ac.at> en nombre de JUAN MANUEL 
PEREZ <jm.perez-m...@ehu.eus>
Enviado: miércoles, 12 de octubre de 2016 12:37:11 p. m.
Para: A Mailing list for WIEN2k users
Asunto: Re: [Wien] Change of structure symmetry


C11m does not exist. It includes a gratuit centering that can be
elliminated by changing the unit cell within the same convention (one unit
cell direction perpendicular to the mirror plane).

But, as said in the previous message,  the symmetry of the discussed
structure keeping the original unit cell would be given rather by the label
Cm11 with the monoclinic axis along a (the alpha angle may be different
from 90 but it is not forced to be different!),  and therefore it does not
correspond to none of the two possible standard settings (monoclinic axis
along b or c) that you have in the Wikipedia.

In any case, it is true that sgroup does not propose the more reasonable
unit cell among those possible in
the standard description of the symmetry as C1m1, and coud have just
interchanged the axes, keeping the three 90 degrees angles. BUT the
identification of symmetries is an algebraic problem where the specific
metrics of the unit cell does not play a role, and all this type of
programs do not care about it. To find the “nicest” unit cell among the
possible ones is beyond them, and if one wants to consider all the possible
cases that one can encounter this unit cell “embellishment process is not
trivial. The best is to identify the “normalizer” of the space group in
the listings available (see for instance the Bilbao server), which defines
the unit cell changes that are possible, and find by hand the one with with
which we are happy.

best regards,

J. Manuel Perez-Mato
Fac. Ciencia y Tecnologia,
Universidad del Pais Vasco, UPV
48080 BILBAO,
Spain

***

> El 12/10/2016, a las 17:51, Laurence Marks <l-ma...@northwestern.edu>
> escribió:
>
> I meant "correct" when the cell is C11m, which is better for Wien.
>
> On Wed, Oct 12, 2016 at 10:50 AM, Laurence Marks
> <l-ma...@northwestern.edu> wrote:
>
>> My two cents worth. If you look at, for
>> instance, https://en.wikipedia.org/wiki/List_of_space_groups, Cm #8 is
>> a monoclinic spacegroup which (in the B11m setting) has beta .ne. 90.
>> It is "correct" to have gamma .ne. 90 for the standard convention.
>> However, this is inconvenient and it would be nice if sgroup made an
>> exception for Wien.
>>
>> On Wed, Oct 12, 2016 at 10:14 AM, Peter Blaha
>> <pbl...@theochem.tuwien.ac.at> wrote:
>>
>>> ===
>>>
>>> The structure that you have attached does NOT have Cmm2 as space group
>>> symmetry, but only Cm, which is the one that sgroup correctly finds.
The
>>> mirror plane of the Cm group is perpendicular to the original a axis,
>>> and
>>> in the standard description of Cm it should be perpendicular to the b
>>> axis.
>>> That is the reason why it interchanges the axes, to make the old a axis
>>> become
>>> the new b one. It is however true that it could have however kept the
>>> original
>>> unit cell metrics, with the axes interchanged. The program indeed does
>>> not
>>> seem to have any particular criterion to optimize the choice of the
unit
>>> cell within the standard description of the space group, and as Peter
>>> Blaha
>>> says there are many possible choices for monoclinic space groups. The
>>> program just chooses one, the reason being that your structure is
>>> monoclinic
>>> with Cm symmetry and not Cmm2.
>>>
>>> J. Manuel Perez-Mato
>>> Fac. Ciencia y Tecnologia,
>>> Universidad del Pais Vasco, UPV
>>> 48080 BILBAO,
>>> Spain
>>> ***
>>>
>>> On 10/12/2016 04:50 AM, delamora wrote:
>>>> I want to see how Cu interacts with the TiO2 surface, so I construct
>>>> with 'supercell' an enlarged cell, with
>>>> SG 35 (C m m 2)

Re: [Wien] Change of structure symmetry

2016-10-12 Thread JUAN MANUEL PEREZ


C11m does not exist. It includes a gratuit centering that can be
elliminated by changing the unit cell within the same convention (one unit
cell direction perpendicular to the mirror plane).

But, as said in the previous message,  the symmetry of the discussed
structure keeping the original unit cell would be given rather by the label
Cm11 with the monoclinic axis along a (the alpha angle may be different
from 90 but it is not forced to be different!),  and therefore it does not
correspond to none of the two possible standard settings (monoclinic axis
along b or c) that you have in the Wikipedia.

In any case, it is true that sgroup does not propose the more reasonable
unit cell among those possible in 
the standard description of the symmetry as C1m1, and coud have just
interchanged the axes, keeping the three 90 degrees angles. BUT the
identification of symmetries is an algebraic problem where the specific
metrics of the unit cell does not play a role, and all this type of
programs do not care about it. To find the “nicest” unit cell among the
possible ones is beyond them, and if one wants to consider all the possible
cases that one can encounter this unit cell “embellishment process is not
trivial. The best is to identify the “normalizer” of the space group in
the listings available (see for instance the Bilbao server), which defines
the unit cell changes that are possible, and find by hand the one with with
which we are happy.

best regards,

J. Manuel Perez-Mato
Fac. Ciencia y Tecnologia,
Universidad del Pais Vasco, UPV
48080 BILBAO,
Spain

***


El 12/10/2016, a las 17:51, Laurence Marks 
escribió:

I meant "correct" when the cell is C11m, which is better for Wien.

On Wed, Oct 12, 2016 at 10:50 AM, Laurence Marks
 wrote:


My two cents worth. If you look at, for
instance, https://en.wikipedia.org/wiki/List_of_space_groups, Cm #8 is
a monoclinic spacegroup which (in the B11m setting) has beta .ne. 90.
It is "correct" to have gamma .ne. 90 for the standard convention.
However, this is inconvenient and it would be nice if sgroup made an
exception for Wien.

On Wed, Oct 12, 2016 at 10:14 AM, Peter Blaha
 wrote:


===

The structure that you have attached does NOT have Cmm2 as space group
symmetry, but only Cm, which is the one that sgroup correctly finds.

The

mirror plane of the Cm group is perpendicular to the original a axis,
and
in the standard description of Cm it should be perpendicular to the b
axis.
That is the reason why it interchanges the axes, to make the old a axis
become
the new b one. It is however true that it could have however kept the
original
unit cell metrics, with the axes interchanged. The program indeed does
not
seem to have any particular criterion to optimize the choice of the

unit

cell within the standard description of the space group, and as Peter
Blaha
says there are many possible choices for monoclinic space groups. The
program just chooses one, the reason being that your structure is
monoclinic
with Cm symmetry and not Cmm2.

J. Manuel Perez-Mato
Fac. Ciencia y Tecnologia,
Universidad del Pais Vasco, UPV
48080 BILBAO,
Spain
***

On 10/12/2016 04:50 AM, delamora wrote:

I want to see how Cu interacts with the TiO2 surface, so I construct
with 'supercell' an enlarged cell, with
SG 35 (C m m 2)
then I attach Cu and O on the surface in a way that I break the
symmetry
in the b direction
The cell is orthorhombic

CXY LATTICE,NONEQUIV.ATOMS: 21
MODE OF CALC=RELA unit=bohr
  11.187184 23.838706 23.838290 90.0 90.0 90.0

if I run initialize calculation and then sgroup the new cell changes

to


CXZ LATTICE,NONEQUIV.ATOMS: 28 8 Cm
MODE OF CALC=RELA unit=bohr
  23.838706 33.712727 11.187184 90.0 90.0 135.000500

which is correct, but it is no longer orthogonal which is awkward, one
angle changes from
90 to 135.0005
also the a, b, c => c, a, b

Also I cannot see the structure with XCrySDen, unless I change the
135.0005 angle by little.

With the new structure and the old one I managed to make a new
TiO2.struct with orthorhombic and can be seen with XCrySDen

It would be nice that sgroup would generate a structure with the
orthorhombic symmetry

               Saludos

                       Pablo de la Mora






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Re: [Wien] Change of structure symmetry

2016-10-12 Thread Laurence Marks
My two cents worth. If you look at, for instance,
https://en.wikipedia.org/wiki/List_of_space_groups, Cm #8 is a monoclinic
spacegroup which (in the B11m setting) has beta .ne. 90. It is "correct" to
have gamma .ne. 90 for the standard convention. However, this is
inconvenient and it would be nice if sgroup made an exception for Wien.

On Wed, Oct 12, 2016 at 10:14 AM, Peter Blaha 
wrote:

> ===
>
> The structure that you have attached does NOT have Cmm2 as space group
> symmetry, but only Cm, which is the one that sgroup correctly finds. The
> mirror plane of the Cm group is perpendicular to the original a axis, and
> in the standard description of Cm it should be perpendicular to the b axis.
> That is the reason why it interchanges the axes, to make the old a axis
> become
> the new b one. It is however true that it could have however kept the
> original
> unit cell metrics, with the axes interchanged. The program indeed does not
> seem to have any particular criterion to optimize the choice of the unit
> cell within the standard description of the space group, and as Peter Blaha
> says there are many possible choices for monoclinic space groups. The
> program just chooses one, the reason being that your structure is
> monoclinic
> with Cm symmetry and not Cmm2.
>
> J. Manuel Perez-Mato
> Fac. Ciencia y Tecnologia,
> Universidad del Pais Vasco, UPV
> 48080 BILBAO,
> Spain
> ***
>
>
> On 10/12/2016 04:50 AM, delamora wrote:
> > I want to see how Cu interacts with the TiO2 surface, so I construct
> > with 'supercell' an enlarged cell, with
> > SG 35 (C m m 2)
> > then I attach Cu and O on the surface in a way that I break the symmetry
> > in the b direction
> > The cell is orthorhombic
> >
> > CXY LATTICE,NONEQUIV.ATOMS: 21
> > MODE OF CALC=RELA unit=bohr
> >  11.187184 23.838706 23.838290 90.0 90.0 90.0
> >
> > if I run initialize calculation and then sgroup the new cell changes to
> >
> > CXZ LATTICE,NONEQUIV.ATOMS: 28 8 Cm
> > MODE OF CALC=RELA unit=bohr
> >  23.838706 33.712727 11.187184 90.0 90.0 135.000500
> >
> > which is correct, but it is no longer orthogonal which is awkward, one
> > angle changes from
> > 90 to 135.0005
> > also the a, b, c => c, a, b
> >
> > Also I cannot see the structure with XCrySDen, unless I change the
> > 135.0005 angle by little.
> >
> > With the new structure and the old one I managed to make a new
> > TiO2.struct with orthorhombic and can be seen with XCrySDen
> >
> > It would be nice that sgroup would generate a structure with the
> > orthorhombic symmetry
> >
> >   Saludos
> >
> >   Pablo de la Mora
> >
> >
> >
> > ___
> > Wien mailing list
> > Wien@zeus.theochem.tuwien.ac.at
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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:
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Re: [Wien] Change of structure symmetry

2016-10-12 Thread Laurence Marks
I meant "correct" when the cell is C11m, which is better for Wien.

On Wed, Oct 12, 2016 at 10:50 AM, Laurence Marks 
wrote:

> My two cents worth. If you look at, for instance, https://en.
> wikipedia.org/wiki/List_of_space_groups, Cm #8 is a monoclinic spacegroup
> which (in the B11m setting) has beta .ne. 90. It is "correct" to have gamma
> .ne. 90 for the standard convention. However, this is inconvenient and it
> would be nice if sgroup made an exception for Wien.
>
> On Wed, Oct 12, 2016 at 10:14 AM, Peter Blaha <
> pbl...@theochem.tuwien.ac.at> wrote:
>
>> ===
>>
>> The structure that you have attached does NOT have Cmm2 as space group
>> symmetry, but only Cm, which is the one that sgroup correctly finds. The
>> mirror plane of the Cm group is perpendicular to the original a axis, and
>> in the standard description of Cm it should be perpendicular to the b
>> axis.
>> That is the reason why it interchanges the axes, to make the old a axis
>> become
>> the new b one. It is however true that it could have however kept the
>> original
>> unit cell metrics, with the axes interchanged. The program indeed does not
>> seem to have any particular criterion to optimize the choice of the unit
>> cell within the standard description of the space group, and as Peter
>> Blaha
>> says there are many possible choices for monoclinic space groups. The
>> program just chooses one, the reason being that your structure is
>> monoclinic
>> with Cm symmetry and not Cmm2.
>>
>> J. Manuel Perez-Mato
>> Fac. Ciencia y Tecnologia,
>> Universidad del Pais Vasco, UPV
>> 48080 BILBAO,
>> Spain
>> ***
>>
>>
>> On 10/12/2016 04:50 AM, delamora wrote:
>> > I want to see how Cu interacts with the TiO2 surface, so I construct
>> > with 'supercell' an enlarged cell, with
>> > SG 35 (C m m 2)
>> > then I attach Cu and O on the surface in a way that I break the symmetry
>> > in the b direction
>> > The cell is orthorhombic
>> >
>> > CXY LATTICE,NONEQUIV.ATOMS: 21
>> > MODE OF CALC=RELA unit=bohr
>> >  11.187184 23.838706 23.838290 90.0 90.0 90.0
>> >
>> > if I run initialize calculation and then sgroup the new cell changes to
>> >
>> > CXZ LATTICE,NONEQUIV.ATOMS: 28 8 Cm
>> > MODE OF CALC=RELA unit=bohr
>> >  23.838706 33.712727 11.187184 90.0 90.0 135.000500
>> >
>> > which is correct, but it is no longer orthogonal which is awkward, one
>> > angle changes from
>> > 90 to 135.0005
>> > also the a, b, c => c, a, b
>> >
>> > Also I cannot see the structure with XCrySDen, unless I change the
>> > 135.0005 angle by little.
>> >
>> > With the new structure and the old one I managed to make a new
>> > TiO2.struct with orthorhombic and can be seen with XCrySDen
>> >
>> > It would be nice that sgroup would generate a structure with the
>> > orthorhombic symmetry
>> >
>> >   Saludos
>> >
>> >   Pablo de la Mora
>> >
>> >
>> >
>> > ___
>> > Wien mailing list
>> > Wien@zeus.theochem.tuwien.ac.at
>> > https://urldefense.proofpoint.com/v2/url?u=http-3A__zeus.the
>> ochem.tuwien.ac.at_mailman_listinfo_wien=CwICAg=yHlS04Hh
>> Braes5BQ9ueu5zKhE7rtNXt_d012z2PA6ws=U_T4PL6jwANfAy4r
>> nxTj8IUxm818jnvqKFdqWLwmqg0=UIz_tYDpioGmLaxB1CnCBXVDaiikF8
>> Qxt6cbXR08z-k=ojPWMOGoECaqOg0dia6WDukTKYKxyteOD0snF0XRq2c=
>> > SEARCH the MAILING-LIST at:  https://urldefense.proofpoint.
>> com/v2/url?u=http-3A__www.mail-2Darchive.com_wien-40zeus.
>> theochem.tuwien.ac.at_index.html=CwICAg=yHlS04HhBraes5
>> BQ9ueu5zKhE7rtNXt_d012z2PA6ws=U_T4PL6jwANfAy4rnxTj8IUxm818
>> jnvqKFdqWLwmqg0=UIz_tYDpioGmLaxB1CnCBXVDaiikF8Qxt6cbXR08z-
>> k=KpDTJaINh510H34fxM-m22vfHGfg73K2pgVk44pH4p8=
>> >
>>
>> --
>>
>>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:
>> https://urldefense.proofpoint.com/v2/url?u=http-3A__www.wien
>> 2k.at=CwICAg=yHlS04HhBraes5BQ9ueu5zKhE7rtNXt_
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>> UIz_tYDpioGmLaxB1CnCBXVDaiikF8Qxt6cbXR08z-k=
>> 0oQkNDJGymzhfb_mzl3xLJsoQIaFIiNng--nVnGykuQ=
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>> 3A__www.imc.tuwien.ac.at_TC-5FBlaha=CwICAg=yHlS04HhBra
>> es5BQ9ueu5zKhE7rtNXt_d012z2PA6ws=U_T4PL6jwANfAy4r
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>> Qxt6cbXR08z-k=lcZJan3wcIPgY1FQmVkBAdIADIr6PxlwAmKWqx3_6xI=
>> 
>> --
>> ___
>> Wien mailing list
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Re: [Wien] Change of structure symmetry

2016-10-12 Thread Peter Blaha

===

The structure that you have attached does NOT have Cmm2 as space group
symmetry, but only Cm, which is the one that sgroup correctly finds. The
mirror plane of the Cm group is perpendicular to the original a axis, and
in the standard description of Cm it should be perpendicular to the b axis.
That is the reason why it interchanges the axes, to make the old a axis 
become
the new b one. It is however true that it could have however kept the 
original

unit cell metrics, with the axes interchanged. The program indeed does not
seem to have any particular criterion to optimize the choice of the unit
cell within the standard description of the space group, and as Peter Blaha
says there are many possible choices for monoclinic space groups. The
program just chooses one, the reason being that your structure is monoclinic
with Cm symmetry and not Cmm2.

J. Manuel Perez-Mato
Fac. Ciencia y Tecnologia,
Universidad del Pais Vasco, UPV
48080 BILBAO,
Spain
***


On 10/12/2016 04:50 AM, delamora wrote:

I want to see how Cu interacts with the TiO2 surface, so I construct
with 'supercell' an enlarged cell, with
SG 35 (C m m 2)
then I attach Cu and O on the surface in a way that I break the symmetry
in the b direction
The cell is orthorhombic

CXY LATTICE,NONEQUIV.ATOMS: 21
MODE OF CALC=RELA unit=bohr
 11.187184 23.838706 23.838290 90.0 90.0 90.0

if I run initialize calculation and then sgroup the new cell changes to

CXZ LATTICE,NONEQUIV.ATOMS: 28 8 Cm
MODE OF CALC=RELA unit=bohr
 23.838706 33.712727 11.187184 90.0 90.0 135.000500

which is correct, but it is no longer orthogonal which is awkward, one
angle changes from
90 to 135.0005
also the a, b, c => c, a, b

Also I cannot see the structure with XCrySDen, unless I change the
135.0005 angle by little.

With the new structure and the old one I managed to make a new
TiO2.struct with orthorhombic and can be seen with XCrySDen

It would be nice that sgroup would generate a structure with the
orthorhombic symmetry

  Saludos

  Pablo de la Mora



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--

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--
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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] Change of structure symmetry

2016-10-11 Thread delamora
Thank you,

No, I do not think that it is crystallographically wrong, it is just the way 
that sgroup chooses to put the lines

This way

.   .   .

  /  /

.   .   .

connecting diagonally

or this way

.   .   .

|  |

.   .   .
connecting vertically

both are correct


De: Wien  en nombre de Laurence Marks 


I agree with you -- it would be nice if 90 was kept although formally I believe 
it is crystallographically wrong. I have never tried to tweak the code as it is 
in C which I don't like much. Maybe someone who likes C can look.

---
Professor Laurence Marks
"Research is to see what everybody else has seen, and to think what nobody else 
has thought", Albert Szent-Gyorgi
http://www.numis.northwestern.edu
Corrosion in 4D http://MURI4D.numis.northwestern.edu
Partner of the CFW 100% gender equity project, 
www.cfw.org/100-percent
Co-Editor, Acta Cryst A


On Oct 11, 2016 21:51, "delamora" > 
wrote:
I want to see how Cu interacts with the TiO2 surface, so I construct with 
'supercell' an enlarged cell, with
SG 35 (C m m 2)
then I attach Cu and O on the surface in a way that I break the symmetry in the 
b direction
The cell is orthorhombic

CXY LATTICE,NONEQUIV.ATOMS: 21
MODE OF CALC=RELA unit=bohr
 11.187184 23.838706 23.838290 90.0 90.0 90.0

if I run initialize calculation and then sgroup the new cell changes to

CXZ LATTICE,NONEQUIV.ATOMS: 28 8 Cm
MODE OF CALC=RELA unit=bohr
 23.838706 33.712727 11.187184 90.0 90.0 135.000500

which is correct, but it is no longer orthogonal which is awkward, one angle 
changes from
90 to 135.0005
also the a, b, c => c, a, b

Also I cannot see the structure with XCrySDen, unless I change the 135.0005 
angle by little.

With the new structure and the old one I managed to make a new TiO2.struct with 
orthorhombic and can be seen with XCrySDen

It would be nice that sgroup would generate a structure with the orthorhombic 
symmetry

  Saludos

  Pablo de la Mora

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Re: [Wien] Change of structure symmetry

2016-10-11 Thread delamora
Thank you,

I have encountered this problem before and I was able to use the orthorhombic 
cell, but in this case the task was much harder, and if sgroup had this ability 
to choose the most "compact" cell it would be nice.

For example a square cell is correct (in 2D), but if one puts lines at 45 
degrees it is also correct in certain cases. Which is what is happening here, 
the program chooses 90+45 degrees instead of 90

I hope to make myself clear



De: Wien <wien-boun...@zeus.theochem.tuwien.ac.at> en nombre de Peter Blaha 
<pbl...@theochem.tuwien.ac.at>
Enviado: miércoles, 12 de octubre de 2016 12:32:03 a. m.
Para: A Mailing list for WIEN2k users
Asunto: Re: [Wien] Change of structure symmetry

It is not always mandatory to take the changes suggested by sgroup into
account. (This is the reason why it is not made automatically). For low
symmetry structures (monoclinic) there are many possible settings and
even the construction of the unit cell is not unique, but arbitrary
equivalent choices exists.

The following "rules" exist: Run

x nn   #  and accept all changes to get the proper multiplicity of the
atoms.
x sgroup   #  and check if sgroup has reduced the unit cell (or changed
the multiplicity). Only in this case you have to accept the changes by
sgroup. ("Reduced" means: the total number of atoms in the cell got
smaller). If sgroup just changed the lattice type or a,b,c,angles; there
is no need to accept the scgroup changes.
To be sure that you can neglect the changes, just  remember the number
of symmetry operations which sgroup has found.

x symmetry  # compare the number of symmetry operations from symmetry
and sgroup. If this is the same (of course, the individual operations
may be different) and symmetry also found identical site symmetry of all
positions, you are save and can simply neglect sgroup.


Am 12.10.2016 um 04:50 schrieb delamora:
> I want to see how Cu interacts with the TiO2 surface, so I construct
> with 'supercell' an enlarged cell, with
> SG 35 (C m m 2)
> then I attach Cu and O on the surface in a way that I break the symmetry
> in the b direction
> The cell is orthorhombic
>
> CXY LATTICE,NONEQUIV.ATOMS: 21
> MODE OF CALC=RELA unit=bohr
>  11.187184 23.838706 23.838290 90.0 90.0 90.0
>
> if I run initialize calculation and then sgroup the new cell changes to
>
> CXZ LATTICE,NONEQUIV.ATOMS: 28 8 Cm
> MODE OF CALC=RELA unit=bohr
>  23.838706 33.712727 11.187184 90.0 90.0 135.000500
>
> which is correct, but it is no longer orthogonal which is awkward, one
> angle changes from
> 90 to 135.0005
> also the a, b, c => c, a, b
>
> Also I cannot see the structure with XCrySDen, unless I change the
> 135.0005 angle by little.
>
> With the new structure and the old one I managed to make a new
> TiO2.struct with orthorhombic and can be seen with XCrySDen
>
> It would be nice that sgroup would generate a structure with the
> orthorhombic symmetry
>
>   Saludos
>
>   Pablo de la Mora
>
>
>
> ___
> Wien mailing list
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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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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] Change of structure symmetry

2016-10-11 Thread Peter Blaha
It is not always mandatory to take the changes suggested by sgroup into 
account. (This is the reason why it is not made automatically). For low 
symmetry structures (monoclinic) there are many possible settings and 
even the construction of the unit cell is not unique, but arbitrary 
equivalent choices exists.


The following "rules" exist: Run

x nn   #  and accept all changes to get the proper multiplicity of the 
atoms.
x sgroup   #  and check if sgroup has reduced the unit cell (or changed 
the multiplicity). Only in this case you have to accept the changes by 
sgroup. ("Reduced" means: the total number of atoms in the cell got 
smaller). If sgroup just changed the lattice type or a,b,c,angles; there 
is no need to accept the scgroup changes.
To be sure that you can neglect the changes, just  remember the number 
of symmetry operations which sgroup has found.


x symmetry  # compare the number of symmetry operations from symmetry 
and sgroup. If this is the same (of course, the individual operations 
may be different) and symmetry also found identical site symmetry of all 
positions, you are save and can simply neglect sgroup.



Am 12.10.2016 um 04:50 schrieb delamora:

I want to see how Cu interacts with the TiO2 surface, so I construct
with 'supercell' an enlarged cell, with
SG 35 (C m m 2)
then I attach Cu and O on the surface in a way that I break the symmetry
in the b direction
The cell is orthorhombic

CXY LATTICE,NONEQUIV.ATOMS: 21
MODE OF CALC=RELA unit=bohr
 11.187184 23.838706 23.838290 90.0 90.0 90.0

if I run initialize calculation and then sgroup the new cell changes to

CXZ LATTICE,NONEQUIV.ATOMS: 28 8 Cm
MODE OF CALC=RELA unit=bohr
 23.838706 33.712727 11.187184 90.0 90.0 135.000500

which is correct, but it is no longer orthogonal which is awkward, one
angle changes from
90 to 135.0005
also the a, b, c => c, a, b

Also I cannot see the structure with XCrySDen, unless I change the
135.0005 angle by little.

With the new structure and the old one I managed to make a new
TiO2.struct with orthorhombic and can be seen with XCrySDen

It would be nice that sgroup would generate a structure with the
orthorhombic symmetry

  Saludos

  Pablo de la Mora



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--
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] Change of structure symmetry

2016-10-11 Thread Laurence Marks
I agree with you -- it would be nice if 90 was kept although formally I
believe it is crystallographically wrong. I have never tried to tweak the
code as it is in C which I don't like much. Maybe someone who likes C can
look.

---
Professor Laurence Marks
"Research is to see what everybody else has seen, and to think what nobody
else has thought", Albert Szent-Gyorgi
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Corrosion in 4D http://MURI4D.numis.northwestern.edu
Partner of the CFW 100% gender equity project, www.cfw.org/100-percent
Co-Editor, Acta Cryst A


On Oct 11, 2016 21:51, "delamora"  wrote:

> I want to see how Cu interacts with the TiO2 surface, so I construct with
> 'supercell' an enlarged cell, with
> SG 35 (C m m 2)
> then I attach Cu and O on the surface in a way that I break the symmetry
> in the b direction
> The cell is orthorhombic
>
> CXY LATTICE,NONEQUIV.ATOMS: 21
> MODE OF CALC=RELA unit=bohr
>  11.187184 23.838706 23.838290 90.0 90.0 90.0
>
> if I run initialize calculation and then sgroup the new cell changes to
>
> CXZ LATTICE,NONEQUIV.ATOMS: 28 8 Cm
> MODE OF CALC=RELA unit=bohr
>  23.838706 33.712727 11.187184 90.0 90.0 135.000500
>
> which is correct, but it is no longer orthogonal which is awkward, one
> angle changes from
> 90 to 135.0005
> also the a, b, c => c, a, b
>
> Also I cannot see the structure with XCrySDen, unless I change the
> 135.0005 angle by little.
>
> With the new structure and the old one I managed to make a new TiO2.struct
> with orthorhombic and can be seen with XCrySDen
>
> It would be nice that sgroup would generate a structure with the
> orthorhombic symmetry
>
>   Saludos
>
>   Pablo de la Mora
>
>
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