Really appreciate last two responses. Thank you both of you Sir.
Everyone helped me on many occasions. I am grateful to all of you.
Best regards
Naseem
On Fri, Jul 4, 2014 at 3:04 PM, Michael Sluydts michael.sluy...@ugent.be
wrote:
Hello Naseem,
The problem you have is a lack of information. The spacegroup and
stoichiometry still give you freedom through wyckoff positions to create a
variety of structures.
There are multiple avenues you can take. The first is to search the
literature and databases (COD: http://www.crystallography.net and ICSD if
you have access to it http://www.fiz-karlsruhe.com/icsd_home.html),
though I did not immediately find anything of interest in COD. If you
cannot find the structure then it becomes a different problem, rather than
determining materials properties you will have to do structure prediction.
Structure prediction is a discipline in itself (literature available) and
can take a lot of time. If you know of similar compounds you may be able to
base yourself on them as a starting point to reduce your search space, then
try a few different configurations for the atoms, optimize your cells and
see what is lowest in energy.
Other more advanced methods are things like genetic algorithms where you
try different structures then combine them and gradually converge to a
candidate for the optimal structure. Software like USPEX exists for this
but I don't think it has been used with wien2k, though interfacing with it
should not be entirely impossible.
Trying to get more details on what you might be looking for is going to be
the first step either way.
Good luck,
Michael Sluydts
Naseem Hassan schreef op 4/07/2014 11:53:
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 wmppe...@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 %2B34%20946012473
fax. +34 946013500 %2B34%20946013500
***
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 pbl...@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
