Dear Kondrin
Thank you for your suggestion. I actually followed the S Ponce lecture
notes from the following link to calculate el-ph coupling constant.
https://indico.ictp.it/event/8301/session/96/contribution/534/material/0/0.pdf.
But in your message here
https://lists.quantum-espresso.org/pipermail/users/2022-September/049463.html
you suggest to include la2f = .true for q2r, matdyn.x files as well. After
that we should post process the files to get lambda value without using
lambda.x. Am I right in understanding your message clearly. ??
Regards
K Ramesh Kumar
Assistant Professor
GITAM, University
Vizag, India
On Thu, Oct 27, 2022 at 1:53 PM Ramesh Kumar Kamadurai <rkama...@gitam.edu>
wrote:
> Dear users
> I am trying to calculate el-Ph coupling constant and other properties for
> a superconductor. The input file is attached. I am a bit stuck with
> VC-Relax calculation as the system is not able to stabilize at 0.0 kbar. I
> followed all the suggestions given in forum
> 1. Increased Cut-off to maximum
> 2. Tried USPP,NC, Mixed and currently running with PBE-Sol
> 3. Sequentially done 2 VC Relax calculation but i am not able to sort out
> the issue.
> &CONTROL
> calculation = "vc-relax"
> etot_conv_thr = 4.00000e-05
> forc_conv_thr = 1.00000e-04
> max_seconds = 1.72800e+05
> nstep = 100
> outdir = "/home/sjacobs/tmp/"
> prefix = "PDZ-VCRELAX"
> pseudo_dir = "C:\Users\RAMESH\.burai\.pseudopot"
> tprnfor = .TRUE.
> tstress = .TRUE.
> verbosity = "high"
> /
>
> &SYSTEM
> a = 6.36512e+00
> degauss = 7.34986e-03
> ecutrho = 6.40000e+02
> ecutwfc = 8.00000e+01
> ibrav = 2
> nat = 4
> nosym = .FALSE.
> nspin = 1
> ntyp = 3
> occupations = "smearing"
> smearing = "marzari-vanderbilt"
> /
>
> &ELECTRONS
> conv_thr = 8.00000e-10
> electron_maxstep = 80
> mixing_beta = 4.00000e-01
> startingpot = "atomic"
> startingwfc = "atomic+random"
> /
>
> &IONS
> ion_dynamics = "bfgs"
> /
>
> &CELL
> cell_dofree = "all"
> cell_dynamics = "bfgs"
> press = 0.00000e+00
> press_conv_thr = 5.00000e-01
> /
>
> K_POINTS {automatic}
> 12 12 12 0 0 0
>
> ATOMIC_SPECIES
> Ga 69.72300 Ga.pbesol-dnl-rrkjus_psl.1.0.0.UPF
> Pd 106.42000 Pd_ONCV_PBEsol-1.0.upf
> Zr 91.22400 zr_pbesol_v1.uspp.F.UPF
>
> ATOMIC_POSITIONS {crystal}
> Zr 0.000000 0.000000 0.000000
> Ga 0.493162 0.493162 0.493162
> Pd 0.739743 0.739743 0.739743
> Pd 0.246581 0.246581 0.246581
>
> The output stress is given below
> entering subroutine stress ...
> total stress (Ry/bohr**3) (kbar) P=
> 2.67
> entering subroutine stress ...
> total stress (Ry/bohr**3) (kbar) P=
> -0.41
> entering subroutine stress ...
> total stress (Ry/bohr**3) (kbar) P=
> -0.82
> entering subroutine stress ...
> total stress (Ry/bohr**3) (kbar) P=
> 0.56
> entering subroutine stress ...
> total stress (Ry/bohr**3) (kbar) P=
> 0.13
> entering subroutine stress ...
> total stress (Ry/bohr**3) (kbar) P=
> -0.08
> entering subroutine stress ...
> total stress (Ry/bohr**3) (kbar) P=
> -0.23
> entering subroutine stress ...
> total stress (Ry/bohr**3) (kbar) P=
> -0.35
> entering subroutine stress ...
> total stress (Ry/bohr**3) (kbar) P=
> -0.50
> entering subroutine stress ...
> total stress (Ry/bohr**3) (kbar) P=
> -0.63
> entering subroutine stress ...
> total stress (Ry/bohr**3) (kbar) P=
> -0.77
> entering subroutine stress ...
> total stress (Ry/bohr**3) (kbar) P=
> -0.83
> My question is
> What is the optimal pressure value to avoid negative frequencies for
> electron phonon calculation ?
> Is there any mistake in my input file ?
> Thanks in advance
> Regards
> Ramesh
> Asst. Professor
> GITAM University
> Vizag, India
>
>
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