Hello Jakob,
you do not give much detail about what you are doing. As said, QHA is
effective when dealing with one degree of freedom (i.e. cubic
semiconductor) but harder to use in any other case. Are you doing a
constant-volume variable-cell relax (aka cell_dofree='shape') for a
series of volumes? And then computing for each volume the Helmholtz free
energy (from the phonons directly or from the dos)? Are you doing this
your self by hand or using one of the available QHA software packages?
The oscillations could be an honest bug, or a difficult integration of
the DOS.
cheers
On 04/11/2022 09:20, Jakob Kraus wrote:
Dear QE users,
I am trying to calculate heat capacities, and to this end, I have
calculated the Gibbs energy as a function of volume
at several temperatures in a range of 0-700 K.
However, the functions that result from this do not show a single
minimum, but rather a whole lot of oscillations, which
seem to originate from the phonons, since the E(V) diagram at 0 K
shows a single minimum as expected.
I am thankful for any help you can offer with getting rid of these
oscillations.
I have attached input files and some plots to showcase the problem.
Best regards,
Jakob Kraus, TU Freiberg
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_______________________________________________
The Quantum ESPRESSO community stands by the Ukrainian
people and expresses its concerns about the devastating
effects that the Russian military offensive has on their
country and on the free and peaceful scientific, cultural,
and economic cooperation amongst peoples
_______________________________________________
Quantum ESPRESSO is supported by MaX (www.max-centre.eu)
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