There is an issue, which is troubling me.
I want to analyse effect of halide mixing in a series A2BC6-xDx.
What I did:
I took the A2BC6---primitive
Relaxed it and then began to substitute atoms progressively. It took different symmetries at different mixing. It was ok for electronic calculations, where setting ibrav zero didn't trouble!!!
When I started elastic calculations using thermopw, it demanded value of ibrav for symmetry. This began troubling me!!!
So I switched to using conventional cell of A2B2C6 and restarted the process of progressive substitution, the issue however is that it is very expensive computationally.
So my question is:
Is substituting in primitive cell allowed?
If yes, how can we set correct ibrav?
The symmetry, lattice constants, i.e., value of ibrav, changes from one format to other (except cubic), of which one is to be considered, primitive or conventional!!!
Although the intrinsic properties like band gap, etc should remain invariant in both formats!!!
Kindly help me here
Regards
Hello Mohammad Ishfaq
I now elastic constants calculation can be troublesome. Have you tried the calculation of the pure A2BC6 ? First, you have to make sure thermo_pw will do the correct calculation of the pure material. Then, about substitution, you have to build it in the way the structure remains somewhat symmetric. But what was the error you got in thermo_pw?
Sincerely,
Dr. Ricardo Tadeu
yes, i calculated for A2B2C6. It works fine. I initially want to know can we substitute in a primitive cell!!! The error arises as wrong ibrav, since it demands non zero value of ibrav!!! If you care i shall share my file in your inbox Sir.
Regards
You may have substituted atoms in some positions that confronts the symmetry of your ibrav. We have to keep in mind that the symmetry is consequence of the atomic positions. We can not determine any ibrav for the structures we build. Probably your new structure will not have the same ibrav than the original A2B2C6. Could you show what is your new structure?
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