[QE-developers] problem in running lambda.x for the calculation of Tc

[Soumendra Kumar Das]

Dear Sir,

I am using quantum espresso for superconductivity Tc calculation. I put
this question last week in the QE users forum (
users at lists.quantum-espresso.org), but I did not get any response.
Therefore I am writing this mail here as I have been getting this trouble
for a long time.

I was trying to calculate the superconducting transition temperature of Pb
and Al given as trial example in the phonon calculation of QE. all the
steps are running successfully. only the last step is giving "NaN" (not a
number).

I am requesting to kindly suggest to me what I should do and why this error
is coming.

I am sending  both the input and output data for lambda.x calculation. The
tutorial file which I was following is also attached here.

###########################################################################
10  0.12  1    ! emax (something more than highest phonon mode in THz),
degauss, smearing method
    8          ! Number of q-points for which EPC is calculated,
    0.0000000  0.0000000  0.0000000   1.00  ! the first q-point, use
kpoints.x program to calculate
    -0.2500000 -0.2500000  0.2500000   8.00  ! q-points and their weight
    -0.5000000 -0.5000000  0.5000000   4.00  !
     0.0000000  0.0000000  0.5000000   6.00  ! 4th q-point, qx,qy,qz
    -0.2500000 -0.2500000  0.7500000  24.00  !
    -0.5000000 -0.5000000  1.0000000  12.00  !
     0.0000000  0.0000000  1.0000000   3.00  !
    -0.5000000  0.0000000  1.0000000   6.00  ! the last q-point
elph_dir/elph.inp_lambda.1 ! elph output file names,
elph_dir/elph.inp_lambda.2 ! in the same order as the q-points before
elph_dir/elph.inp_lambda.3
elph_dir/elph.inp_lambda.4
elph_dir/elph.inp_lambda.5
elph_dir/elph.inp_lambda.6
elph_dir/elph.inp_lambda.7
elph_dir/elph.inp_lambda.8
0.10                     ! \mu the Coloumb coefficient in the modified
                         ! Allen-Dynes formula for T_c (via \omega_log)

######################################################################

     lambda = 0.242639 (        NaN )  <log w>=      NaN K  N(Ef)=
 1.294938 at degauss= 0.005
     lambda = 0.350909 (        NaN )  <log w>=      NaN K  N(Ef)=
 1.845335 at degauss= 0.010
     lambda = 0.348256 (        NaN )  <log w>=      NaN K  N(Ef)=
 2.071123 at degauss= 0.015
     lambda = 0.324666 (        NaN )  <log w>=      NaN K  N(Ef)=
 2.196774 at degauss= 0.020
     lambda = 0.302942 (        NaN )  <log w>=      NaN K  N(Ef)=
 2.275654 at degauss= 0.025
     lambda = 0.289683 (        NaN )  <log w>=      NaN K  N(Ef)=
 2.340134 at degauss= 0.030
     lambda = 0.283603 (        NaN )  <log w>=      NaN K  N(Ef)=
 2.397743 at degauss= 0.035
     lambda = 0.281253 (        NaN )  <log w>=      NaN K  N(Ef)=
 2.449225 at degauss= 0.040
     lambda = 0.280253 (        NaN )  <log w>=      NaN K  N(Ef)=
 2.493764 at degauss= 0.045
     lambda = 0.279197 (        NaN )  <log w>=      NaN K  N(Ef)=
 2.530433 at degauss= 0.050
lambda        omega_log          T_c
   0.24264           NaN                NaN
   0.35091           NaN                NaN
   0.34826           NaN                NaN
   0.32467           NaN                NaN
   0.30294           NaN                NaN
   0.28968           NaN                NaN
   0.28360           NaN                NaN
   0.28125           NaN                NaN
   0.28025           NaN                NaN
   0.27920           NaN                NaN


-- 
*---------------------------------------*
*Thanks and Regards*
*Soumendra Kumar Das*
*Postdoc. Research Scholar*
*School of Physical Sciences*
*National Institute of Science Education and Research (NISER), *
*Bhubaneswar*
*PO- Bhimpur-Padanpur, Via- Jatni, District:- Khurda*

*PIN – 752050, Odisha, INDIA*
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.quantum-espresso.org/pipermail/developers/attachments/20220626/d492d0a1/attachment.html>