[Pw_forum] lattice parameter in 'vc-relax' mode doesn't change

[Sokseiha Muy]

Dear all QE users,

I'm using QE to study the properties of BaF2 which is a cubic material. I notice that when I used the option 'vc-relax' to optimized my structure, in the output the volume of the unit cell change as expected but the lattice parameter is the same for every step. Since the unit cell is cubic, it is contradictory that the volume change while the lattice parameter remains constant.
Is this an error or is there any explanation that I'm not aware of?

Thank you in advance for your help.
Seiha.


Sokseiha MUY,
Department of Materials Science and Engineering,
MIT.
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