[Wien] Guidance require for structure generation

[Pascal BOULET]

Hello Naseem,

Maybe there is a misunderstanding here. 

The point is NOT that people don't want to help you on that topic; the point is that they just CANNOT do it.

The starting point of doing electronic structure calculation is the knowledge of ALL the crystallographic data on the system. That means: Bravais lattice, symmetry group AND ALL the atomic coordinates.

Bravais lattice and symmetry group are not sufficient. You have to find ALL the atomic coordinates. And the Bilbao Crystallographic server cannot help you for this. 

You have to search  into crystallographic journals for your specific compound. If your compound is not available (maybe it is new) then you have to prepare it experimentally, run X-ray experiments and extracts atomic coordinates from the diffractograms (I guess from Rietvelt refinement).

Best regards

Naseem Hassan <raheskoon at gmail.com> wrote:Thank You All.

I benefited from all of you on mailing list. You are absolutely right I should learn instead of spoon feeding. I can understand fully that experts are already handling the burden of below average questions. 

Inspite of all your recommendation I wish that someone should suggest a road map of topics that leads to solution of making new structure in WIEN2k. I see many emails on mailing list that suggest the similar kind of problem of making structure for a specific space group. I really wanted to learn this but always lost in multiple topics. Many of seniors to whom I know personally know can not solve this problem. Just suggesting, that it will beneficial for newcomers if someone can prepare a tutorial on this issue. We sometimes do not work on compounds just because we cannot make structure file in wien2k.

Best Regards
Naseem
    

On Fri, Jul 4, 2014 at 1:16 PM, Juan Manuel Perez Mato <wmppemam at lg.ehu.es> wrote:
Please, learn some elementary crystallography in the International year of crystallography.
regards,
J. Manuel Perez-Mato
Fac. Ciencia y Tecnologia,
Universidad del Pais Vasco, UPV
48080 BILBAO,
Spain

tel. +34 946012473
fax. +34 946013500
***************************************************

El 04/07/2014, a las 02:37, Naseem Hassan escribió:
Dear Sir,

Every space group has some ideal positions. From little experience in the past, I believe on selecting 3 atoms in the start of structure generation and assigning positions for three atoms will give the primitive cell for this space group. In this primitive cell other positions appear automatically by Wien2k. Does a space group has not ideal positions ?. I need ideal positions for three atoms and then I will relax the structure to actual positions for this compound. Modeling a material is possible without experimental results. I am hopeful that you will propose some kind of solution. 

Thank you
Best Regards
Naseem Hassan

On Fri, Jul 4, 2014 at 1:22 AM, Peter Blaha <pblaha at theochem.tuwien.ac.at> wrote:
Without atomic positions one cannot create a structure.

Am 03.07.2014 19:46, schrieb Naseem Hassan:
Dear Wien2k experts

I am reporting this difficulty after going through mailing list and
literature review. Kindly guide how can I generate structure file with
the following information.

Compound Formula:           V3S7Cl
Space Group:                     C mmm#65 Orthorhombic
lattice parameters:              a=20.6   b=3.8, c=3.9

I need *general structure file* for this compound I will try to remove
error associated with RMTs and other initializing parameters by my self.

Alternatively,

If I select 3 atoms in the structure generation and I insert all the
parameters as stated above then I just miss the position of three atoms
in the structure file. In order to fill the positions I checked the
wycoff psoitions from the Bilbao Crystallographic server but I am unable
to understand which position should I give. *If this approach is
correct* then kindly just *provide the positions* which I can fill at
least ideal positions for this kind of space group so that I can fill
and later on I will relax my structure to get actual positons. Kindly do
guide.

Best Regards
Naseem Hassan

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>-----------------
Pascal Boulet
Aix-Marseille University 
MADIREL Laboratory
Avenue Normandie-Niemen
13397 Marseille Cedex 20
Email: pascal.boulet at univ-amu.fr
Tel. +33 413 55 18 10
Fax  +33 413 55 18 50
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