Dear Ramesh,
Yes, you are right. If you include option la2F=.true. Matdyn.x program will
calculate lambda file. All examples in tuturial of S. Ponce include this
option. Resulting lambda file is presented in page 7 of the same tutorial.
Sincerely yours,
M. Kondrin
On Oct 28 2022, Ramesh Kumar Kamadurai wrote:
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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