[Thermo_pw-forum] Error in calculation

[Cristiano Malica]

Hi! Make sure that all the phonon frequencies are positive
for all the geometries of the grid. If not, try to reduce
the grid (with the variables ngeo and step_ngeo) in the 'mur_lc_t' calculation.
Check also that the temperature dependent lattice
constant is contained in the grid of geometries chosen
(if not, you should modify the grid or change the range of temperatures).

Cristiano
________________________________
From: Thermo_pw-forum <thermo_pw-forum-bounces at lists.quantum-espresso.org> on behalf of benamrani, ammar <ammar.benamrani at univ-bba.dz>
Sent: Friday, August 13, 2021 1:21 PM
To: thermo_pw-forum at lists.quantum-espresso.org <thermo_pw-forum at lists.quantum-espresso.org>
Subject: [Thermo_pw-forum] Error in calculation

Hello All Thermo-pw users and experts,

I tried to study the effect of temperature on elastic constants of GaSb binary semiconductor using thermo_pw code.
I used Quasi harmonic approximation (QHA) which is time consuming compared to Quasi static approximation. The calculation is two steps calculation and the error occurred in the second step as follows :
from find_quartic_extremum : error # 1
extremum not found
Any suggestion to solve the issue !
I don't know how to solve this problem.
Any suggestion is appréciated.
Dr. Benamrani Ammar
Faculty of Sciences and Technology
University of Bordj Bou Arréridj

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