Dear Sir For your first two points, I convinced but below suggestions triggered me to ask/clarify my doubts more:
> Note that depending on what you want to compare in your series of > calculations it probably is a good idea to do all calculations in the same > space group - even if you are left with very low symmetry. Do this by > giving all Cr in the pristine cell you want to substitute a different index > (Cr1, Cr2 ...). > I tried to label all Cl with a number and then replaced all Cl one by one with Br. But when I initialised the structure it gives me 1-P1 SG with reduced basis vectors and all angles =60deg. I wounder how to keep all six structure in the same space group? I just had an discussion with experimentlist and he suggested me that changing of basis vector and SG is normal but the key point I have to keep in mind that the SG should not leave the the SG family belonging to that class of (here perovskite) crystal structure. For example: we have various SGs for perovskite family (225, 42, 44, 107..., etc.) and after replacing any number of Cl with Br should stabilise in one the SG belongs to perovskite structure. > > And remember that you do not calculate an (random) alloy, you calculate a > periodic structure. Watch out for superstructure effects, perhaps by > checking larger supercells with the same Br-concentration but different > configuration. > > Sir, I am doing for bulk only like ABCl_(1-x)Br_x. Regards Bhamu > Martin Pieper > > > Am 09.05.2017 01:55, schrieb Dr. K. C. Bhamu: > >> Dear Wien2k Users >> >> I am alloying a quaternery compound: replacing Cr with Br one by one. >> What I see is, the pristine compound is cubic with 225 SG. When I >> replace Cl by Br one by one then lattice parameters deviates from >> cubic to different structure. >> like a=b, c or a,b,c. SG also changes. >> During initialisation I accepted the new structure suggested by the >> w2web. Should I accept the suggested structure? >> As per my understanding from previous posts from mailing list we >> should accept the suggested structure which is with lower symmetry. >> >> Is the change of lattice parameters is normal behaviour of material or >> I am doing any mistake? >> >> Sincerely >> >> Bhamu >> _______________________________________________ >> 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 >> > --- > Dr. Martin Pieper > Karl-Franzens University > Institute of Physics > Universitätsplatz 5 > A-8010 Graz > Austria > Tel.: +43-(0)316-380-8564 > > > > _______________________________________________ > 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/wi > e...@zeus.theochem.tuwien.ac.at/index.html >
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