"branch" picked up by
the system and should remain invariant.
thanks
From: "Amar Singh"<amarsingh122...@rediffmail.com>
Sent: Wed, 22 Jun 2022 18:16:26
To: "users"<users@lists.quantum-espresso.org>
Subject: Re: Polarization calculation using nscf
What I
What I understood up to now is that the bracketed number (mode 0.5099 C/m2) is,
what the reference calls the "quantum of polarization", and it
depends upon the size and choice of the unit-cell selected. On the other hand,
the number outside bracket is the "change in polarization", which is
typi
Hi,
My NSCF calculation on BaTiO3 resulted in a polarization value in o/p file as
"P = -0.2274527 (mod 0.5081493) C/m^2"
along {001} direction.
How should I read this? Is the polarization 0.22 C/m^2? What is this number
0.508?
Thanks
Amar
__
Hi, I am trying to run SCF calculation for a transition metal doped crystal
using PBE/PBEsol PPs. For the original structure (without transition
metal) SCF converges easily with both PBE ad PBEsol. However, as soon as I
replace an atom with transition atom, SCF convergence does not take place wi
Hi Friends,I am trying to use Noose thermostat for CP of a insulator oxide
molecule. According to the previously reported vibration spectra, oscillation
frequency should lie at about 12 THz. Though it did not seem to be working, as
I am getting a fluctuation of tempp about 1000% of set value (T
Dear Friends,I am trying to do CP-MD on a small unit (10 atoms, to start with)
following the steps recommended in different examples/user guide. Everything
converges fine for achieving electronic ground state and ion relaxation. As
soon as I start CP dynamics with verlet, tempp starts to shoot
Dear Friends,I am trying to understand CP-MD to optimize a structure at room
temperature. Right now, I am struggling to understand the parameters like
emass, emass cutoff, ion velocities and nrb etc and how to optimize (decide)
their best possible values for a certain case. I would be thankful
Dear Friends,I am trying a vc-relax on a 320 atom supercell on a 40
processor/256 GB RAM system. As soon as the first iteration starts, run is
terminated with following message.mpi has noticed that process rank 14 with PID
25185 n node Linux-mix excited on signal 9 (killed).With increasing num
Dear Lorenzo Paulatto,Thanks for the response. I have few questions based
upon some literature I found online.1. I found somewhere that open-mpi may
provide parallelization upto few processors, but not for a large number of
them. If so, could MPI be a better option. 2. I do not have Intel MK
Dear Lorenzo Paulatto & Sitangshu Bhattacharya,Thanks for your
suggestions.I did try to check the computing performance with respect to no of
processors for a ten atom unit. I found that computation time is minimum for 8
processors (k 4 4 4) and increases on moving on either side. Similarly, v
Dear Dr. Bhattacharya,Thanks for the link. Though, being very naïve to
such computation, I am not able to figure out the best possible set of
parameters I should start with. Would be thankful if you can suggest some
typical values for -np, -ni, -nk, -nt and -nd for the system with 40 processors
Dear Friends,I am trying to vc-relax a 40 atom supercell using a 40
processor/256GB RAM (Dell 7910) computer equipped with open-mpi. Following is
the command I used to run the QEmpirun pw.x -np 40 < XXX.in > XXX.outI
noticed that the processing speed is slightly better than single processor,
Dear Friends,I want to optimize a structure with nonzero tot_charge and having
issue with the conversion. I read on forum that Makov-Payne correction may help
in conversion, but works only for cubic systems. Is there a way to use M-P
correction for non-cubic system ? If not, what could be the ne
Dear Friends,My vc-relax *.out file shows the same celldm parameters at the
end of file as in the beginning, though the volume of cell has changed. Why it
is so, and how can I find the new optimized lattice parameters.Can any software
convert this *.out file to *.cif or any other format where I
Hi Friends,I am trying to optimize a supercell using vc-relax using ibrav =
14, unit cell volume keeps on shrinking and finally ends up with an error
"Not enough space allocated for radial FFT: try restarting with a larger
cell_factor". Using cell factor = 8 and ecutrho = 10 X ecutwfc helped a
Hi Friends,I am trying to optimize a supercell using vc-relax. In a first
step, I used the space group to optimize one unit cell which gives a reasonable
cell volume. Later, when I tried using same unit cell to optimize a supercell
using ibrav = 14, unit cell volume keeps on shrinking and final
Hi Friends,I am tryin to optimize a supercell using vc-relax. In a first step,
I used the space group to optimize one unit cell which gives a reasonable cell
volume. Later, when I tried using same unit cell to optimize a supercell using
ibrav = 14, unit cell volume keeps on shrinking and finall
Dear Friends,I have a rhombohedral unit cell of ten atoms (two molecules per
cell). I want to form a supercell of this structure having 40 atoms, but its
sides are not be parallel to the lattice vectors of original unit cell. My
first impression is that I can't use the original lattice paramete
Dear Friends,I have a rhombohedral unit cell of ten atoms (two molecules per
cell). I want to form a supercell of this structure having 40 atoms, but its
sides are not be parallel to the lattice vectors of original unit cell. My
first impression is that I can't use the original lattice paramete
Dear Friends,I am trying to install QE on my i7/ Windows 10 computer through
Virtual box/Ubuntu so that I can use more than one processor. I found some
instructions on the forum
(http://qe-forge.org/pipermail/pw_forum/2016-August/110757.html) and tried to
follow them.I have already installed f
Dear Friends,How can we represent F centers in a structure for QE
calculations. F centers basically mean removing a oxygen from the structure and
placing none, one or two electrons at the vacancy (respectively F+2, F+1 and F0
centers). As a result, the unit cell will have a net charge of +2, +1
Hi Friends, I am trying to use pw.x (and pw.exe before) for a structure
optimization. Initially I was using QE5.3 on windows 10 and was encountering
"Error in routine Invmat (1) : error in DGETRF" error. I found on
forum (http://qe-forge.org/pipermail/pw_forum/2014-September/105120.html) that
Dear Paolo Giannozzi , Thanks for your valuable suggestion, it helped up
to some extent. I really appreciate your help.I tried your suggestion, with
approximate values of lattice parameters for rhombohedral setting (as I have
lattice parameters for only hexagonal settings). Following is the par
Dear Friends,I am trying to use R3c space group for BaTiO3 with hexagonal unit
cell. Space group R3C (no. 161) should generate 6 units of BaTiO3. While in QE,
space group 161 is correctly generating 6 Ba and Ti, O atoms are also 6 in
numbers, which should be 18. I also confirmed the positions
Thanks for the suggestion Paolo Giannozzi. Removing ibrav working fine
partially. Space group R3C (no. 161) itself generated six equivalent positions
for Ba and Ti, which is correct according to the known structure. Though, even
generated O atoms are six in numbers, which should be 18. I also
positions of all atoms by another software (Diamond) and it is able to generate
18 O atoms along with six Ba & Ti. Would be thankful for any suggestion on
that.thanksASFrom: "Amar
Singh"<amarsingh122...@rediffmail.com>Sent: Mon, 18 Sep 2017
20:55:14To: <pw_forum@pwscf.o
Dear Friends,Its my first appearance on forum and hope I can reach you via
pw_forum@pwscf.org. I am trying to optimize the structure of BaTiO3 in R3C
space group (No. 161). I am using the lattice parameters as suggested on QE
website, Celldm (1) = a (bohr) and Celldm (3) = c/a. While b = a and
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