[QE-users] Why do I get a warning when using PWTK with HSE?

[Tone Kokalj]

Dear Salma,

It would be much easier to help if you shared your PWTK script or at
least the pw.x input.

Best regards,
Tone
-- 
Jožef Stefan Institute, Ljubljana, Slovenia

On Tue, 2023-07-11 at 09:26 +0000, NAIMI SALMA wrote:
> Hello everyone,
> 
> As I couldn't get the optimized lattice parameter for my material by
> vc-relax calculation, I used pwtk to get the optimized lattice
> parameter of my material with HSE.
> 
> In the input I used the experimental lattice parameter. But for the
> last calculated 2 points I get a warning in the terminal that the
> used a0 is too small even though that I used the experimantal one.
> That's the message that I receive :
> 
> ```
> ---------------------------------------------------------------------
> ---
> WARNING: from get2pV0_: two-point Murnaghan estimation of lattice-
> parameter failed.
>                   The initial a0 was too small.
> ---------------------------------------------------------------------
> ---
> 
>       poor-man estimate of unit-cell volume :  V0 =  3536.06 bohr^3
>       poor-man estimate of lattice-parameter:  a0 =    15.23 bohr
> 
> 
>       warning: minimum is not bracketed yet, calculating another
>                estimator point.
> 
>       * calculating estimator point #.5 :  a =  15.997 bohr
> 
>       Executable: /home/salma/Desktop/qe-7.0/bin/pw.x
>       Running: pw.x -in my_input.d/my_input.estimator-5.in >
> my_input.d/my_input.estimator-5.out
> 
> 
>       * E(tot) = -566.98612068 ryd
>       * P      = 7.34 kbar
> 
> 
>       warning: minimum is not bracketed yet, calculating another
>                estimator point.
> ABORT: cannot guess correct a0 in 5 steps. Initial a0 must be too far
> off, retry with better a0 estimation.
> ABORT statement executed in: run_auto_ my_input.d/my_input
> ```
> 
> How can I solve this problem, please?
> 
> 
> PS: I didn't face the same issue when working with PWTK and GGA, I
> got a lattice parameter close to the experimental one in the output.
> 
> 
> 
> 
> 
> 
> 
> ------------------------------------------------------------ 
> Salma NAIMI
> PhD student - Mohamed 5 University-Rabat
> 
> 
> 
> 
> 
> 
> 
> 
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