<div dir="ltr">Dear Tran and F. Gerhard<div><span style="white-space:nowrap">Many thanks for your help. With me the Cohesive Energies for NI and Fe are 5.53 eV/atom and 5.92eV/atom</span></div></div><div class="gmail_extra"><br><div class="gmail_quote">On Thu, Jan 1, 2015 at 3:36 PM, <span dir="ltr"><<a href="mailto:tran@theochem.tuwien.ac.at" target="_blank">tran@theochem.tuwien.ac.at</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">From the total energies it's difficult to say. It's better to<br>
compare the cohesive energies. My cohesive energies for Fe and Ni<br>
with the WC functional are 5.54 and 5.38 eV/atom, respectively, with<br>
an error bar of 0.05 eV/atom maximum. In this paper you can find<br>
PBE cohesive energies calculated with the VASP code (my PBE values<br>
agree very well with them):<br>
<a href="http://journals.aps.org/prb/abstract/10.1103/PhysRevB.87.214102" target="_blank">http://journals.aps.org/prb/<u></u>abstract/10.1103/PhysRevB.87.<u></u>214102</a><br>
<br>
You have to know which error is acceptable for your purposes.<div class="HOEnZb"><div class="h5"><br>
<br>
<br>
On Thu, 1 Jan 2015, Muhammad Sajjad wrote:<br>
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Dear Tran Thank you for your further help. I am also attaching here with the structure file. Please let know the E0 values you calculated for Ni and Fe. With me<br>
these values are -3040.43215615 and -2544.39535597 (in Ry) respectively.<br>
<br>
On Tue, Dec 30, 2014 at 4:52 AM, <<a href="mailto:tran@theochem.tuwien.ac.at" target="_blank">tran@theochem.tuwien.ac.at</a>> wrote:<br>
Hi,<br>
<br>
The struct file that I used is attached. For my purpose, the size of<br>
the unit cell was large enough to avoid spurious interactions between<br>
neighbouring cells. Note that a, b and c are different in order to avoid<br>
to high symmetry.<br>
<br>
F. Tran<br>
<br>
On Mon, 29 Dec 2014, Muhammad Sajjad wrote:<br>
<br>
Dear Prof. Marks and F. TranThank you so much for your helpful suggestions. I was already doing the spin polarization calculations. I<br>
have got the convergence<br>
by using<br>
mixing factor 0.1, starting calculation with PRATT and then switched to MSR1 after 7 cycles, and the command runsp_lapw -cc 0.00001<br>
-in1ef -i 150<br>
The obtained magnetic moment was 2.00009.<br>
<br>
Dear Tran I would really appreciate if you share some more details about case.struct file. It will definitely be helpful for me as well<br>
as for others. <br>
<br>
Kind Regards<br>
Dr. Sajjad<br>
<br>
On Mon, Dec 29, 2014 at 3:50 AM, <<a href="mailto:tran@theochem.tuwien.ac.at" target="_blank">tran@theochem.tuwien.ac.at</a>> wrote:<br>
The calculation for an isolated atom with a code which uses periodic<br>
boundary conditions (like WIEN2k) is not trivial. This is what I have done<br>
recently for most atoms of the periodic table (excluding f-systems), and<br>
for some of the transition-metal atoms this was extremely difficult to<br>
achieve convergence.<br>
<br>
A few hints (that I used):<br>
<br>
1) It is important (and necessary depending on the atom) to reduce the<br>
symmetry from cubic to, e.g., orthorhombic to be able to access the<br>
electronic configuration with the lowest energy (this is the procedure<br>
followed by several research groups like VASP for instance).<br>
If necessary I can give more details about the case.struct that I used.<br>
<br>
2) lapw0 requires a lot of memory, while lapw1 requires both<br>
memory and time. To reduce computer time for lapw1, I was using<br>
iterative digonalization (this was my command for all atoms):<br>
runsp_lapw -ec 0.0001 -cc 0.0001 -it -i 1000 -NI<br>
<br>
3) For the Ni atom the magnetic moment should be 2:<br>
:MMTOT: SPIN MAGNETIC MOMENT IN CELL = 2.00238<br>
<br>
4) I was using the default setting for mixer.<br>
<br>
F. Tran<br>
<br>
On Sun, 28 Dec 2014, Laurence Marks wrote:<br>
<br>
<br>
Also, only 1 k-point (Gamma), an RMT and RKMax similar to what you use for<br>
bulk Ni, particularly as I assume you are doing the calculation to get an<br>
enthalpy of formation. You may have to use the mpi versions as it is<br>
probably too large for a non-mpi run.<br>
<br>
If you are doing WC+U (or -ineece) the U (or on-site hybrid) removes the<br>
phase transition so convergence should be simple.<br>
<br>
Straight WC is not a simple calculation because the physics for an isolated<br>
Ni atom is wrong. With wrong physics there is in fact no guarantee that the<br>
calculation will ever converge!<br>
<br>
___________________________<br>
Professor Laurence Marks<br>
Department of Materials Science and Engineering<br>
Northwestern University<br>
<a href="http://www.numis.northwestern.edu" target="_blank">www.numis.northwestern.edu</a><br>
<a href="http://MURI4D.numis.northwestern.edu" target="_blank">MURI4D.numis.northwestern.edu</a><br>
Co-Editor, Acta Cryst A<br>
"Research is to see what everybody else has seen, and to think what nobody<br>
else has thought"<br>
Albert Szent-Gyorgi<br>
<br>
On Dec 28, 2014 11:47 AM, "Laurence Marks" <<a href="mailto:L-marks@northwestern.edu" target="_blank">L-marks@northwestern.edu</a>> wrote:<br>
<br>
You almost certainly need to run spin polarized, probably MSR1<br>
(GREED 0.1), TEMPS (room temp). The convergence is complicated<br>
for WC (& simple GGAs) due to an electronic phase transition<br>
between sp & d occupation near the fixed point.<br>
<br>
___________________________<br>
Professor Laurence Marks<br>
Department of Materials Science and Engineering<br>
Northwestern University<br>
<a href="http://www.numis.northwestern.edu" target="_blank">www.numis.northwestern.edu</a><br>
<a href="http://MURI4D.numis.northwestern.edu" target="_blank">MURI4D.numis.northwestern.edu</a><br>
Co-Editor, Acta Cryst A<br>
"Research is to see what everybody else has seen, and to think<br>
what nobody else has thought"<br>
Albert Szent-Gyorgi<br>
<br>
On Dec 28, 2014 10:47 AM, "Muhammad Sajjad" <<a href="mailto:sajjadpu@gmail.com" target="_blank">sajjadpu@gmail.com</a>><br>
wrote:<br>
Dear Users I am running SCF calculation for Ni with<br>
lattice constant of 30 Bohr and using WC-GGA. The<br>
calculation is not converging even upto 100<br>
iterations and more. To solve the problem I have<br>
performed following steps<br>
<br>
switched to TEMPS = 0.005 from TETRA<br>
Changed MSR1 to PRATT<br>
changed mixing factor (increase and decrease from 0.2)<br>
<br>
Thanking in advance. <br>
<br>
Dr. Sajjad<br>
<br>
<br>
<br>
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