[Pw_forum] relaxation of perovskite structure

[Bipul Rakshit]

Dear PWSCF users,
I want to do structural relaxation calculation on LaMnO3 (insulating
antiferromagnet). And I am having few question for doing relaxation of a=b#c
type of compounds.

1. Do I have to simply run the vc-relax calculation and the results at the
end gives relaxed structure?
2. Do after relaxation the final Pressure P= , I got very low?
3. I have run the vc-relax calculation (still running). During calculation I
find that although pressure reaches comparitively lower value ~ -2.01 kbar,
but the (3x3) stress tensor matrix, the off diagonal although zero, but the
on-diagonal elements do show 11.52 Kbar pressure also............
So my question is, why I am not getting total pressure P and all the
on-diagonal element appreciable of some very low value?
What more option I have to use in input file for my point 3?

Kindly guide me for the same.
regards

-- 
Dr. Bipul Rakshit
Research Associate,
S N Bose Centre for Basic Sciences,
Salt Lake,
Kolkata 700 098
India
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