Dear Profs. Blaha and Marks,
Thank you for your comments, it helps.
I indeed made a mistake of starting with asymmetric slab - first I did
Fe atom only on one side of MgO, relaxed it, and then added another Fe
atom on the other side of MgO. When starting with symmetric Fe/MgO/Fe
slab things behave as expected. I wanted to check if there is much
difference between having Fe atom on one or on both sides of the slab.
I am still using iMac computer with i7-3770 and 16 GB of RAM (perhaps I
should really move to the cluster...), and my new external hard drive
was not formatted to see case sensitive file names (Mac operating system
allows things like this!). This is why I had issues with case.inm and
case.inM filenames but it is fixed now.
For now I am happy with structure relaxation results and I like how it
is done with MSR1a. On iMac I cannot really do much more than 6-8
monolayer slab (I want to calculate dense k-point mesh later), but I
think it will be sufficient for my purpose (I am currently checking if
there is much difference between different slab thicknesses).
Best,
Lukasz
On 6/1/2018 1:16 PM, Lukasz Plucinski wrote:
-------- Forwarded Message --------
Subject: Re: [Wien] Structure optimization
Date: Sat, 19 May 2018 09:06:33 -0500
From: Laurence Marks <l-ma...@northwestern.edu>
Reply-To: A Mailing list for WIEN2k users
<wien@zeus.theochem.tuwien.ac.at>
To: A Mailing list for WIEN2k users <wien@zeus.theochem.tuwien.ac.at>
It works...but (sorry Peter) it can be bad science. There are special
cases where it is appropriate, but it can also be very inappropriate.
There is a long history of people fixing some atomic positions to bulk
positions when performing surface calculations. However, the strain
field of any surface decays exponentially in the selvedge layer, and
removing this can be very wrong. For instance, there are many known
cases where the surface induces a ferroelectric distortion which fixed
positions will prevent from happening. The rigorous method is to check
that the atomic positions in the center of the slab are "close enough"
to those in the bulk. If they are not then either the slab needs to be
thicker or there has been a surface induced phase transition.
And, fixing positions for a surface /in general does not improve the
convergence/. If you are lucky it will, but not in general. The reason
(as I have mentioned before) is that the convergence scales with the
number and width of the eigenvalue clusters, not the number of
variables. If the convergence of Wien2k and other DFT codes scaled
with the number of density variables, the methods would be useless!
DFT is a useful method because it will typically converge in 10-100
scf iterations because there are only a few eigenvector clusters of
the dielectric response (in density only calculations) and the force
matrix (with PORT). MSR1a is typically efficient because the number
and width of the clusters of the general dielectric response with both
density and electronic terms included is smaller than the product of
the clusters for the electronic and atomic components.
Sorry for being so pedantic...but rigor matters.
On Sat, May 19, 2018 at 7:56 AM, Peter Blaha
<pbl...@theochem.tuwien.ac.at <mailto:pbl...@theochem.tuwien.ac.at>>
wrote:
> - How can I lock some atoms in position during structure optimization?
In case.inM put the 1.0 values of x,y and/or z of the corresponding
atom (line) to 0.0.
It works well. We do it all the time....
>
> Best,
> Lukasz
>
--
--------------------------------------------------------------------------
Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
Phone: +43-1-58801-165300 FAX: +43-1-58801-165982
Email: bl...@theochem.tuwien.ac.at
<mailto:bl...@theochem.tuwien.ac.at> WIEN2k:
https://urldefense.proofpoint.com/v2/url?u=http-3A__www.wien2k.at&d=DwICAg&c=yHlS04HhBraes5BQ9ueu5zKhE7rtNXt_d012z2PA6ws&r=U_T4PL6jwANfAy4rnxTj8IUxm818jnvqKFdqWLwmqg0&m=HGBSlLfU5SbOh_JfodIoRVa6I69Rsj216R2i2idPWPA&s=Z18mJHtLP0OuMpkNbZyk6BppzH7a7iqaKjSmbAxk0Cw&e=
<https://urldefense.proofpoint.com/v2/url?u=http-3A__www.wien2k.at&d=DwICAg&c=yHlS04HhBraes5BQ9ueu5zKhE7rtNXt_d012z2PA6ws&r=U_T4PL6jwANfAy4rnxTj8IUxm818jnvqKFdqWLwmqg0&m=HGBSlLfU5SbOh_JfodIoRVa6I69Rsj216R2i2idPWPA&s=Z18mJHtLP0OuMpkNbZyk6BppzH7a7iqaKjSmbAxk0Cw&e=>
WWW:
https://urldefense.proofpoint.com/v2/url?u=http-3A__www.imc.tuwien.ac.at_tc-5Fblaha-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D&d=DwICAg&c=yHlS04HhBraes5BQ9ueu5zKhE7rtNXt_d012z2PA6ws&r=U_T4PL6jwANfAy4rnxTj8IUxm818jnvqKFdqWLwmqg0&m=HGBSlLfU5SbOh_JfodIoRVa6I69Rsj216R2i2idPWPA&s=GxPbnc8632eZdJgUG2LT9xuLo25j8wmiwf7mi35vykc&e=
<https://urldefense.proofpoint.com/v2/url?u=http-3A__www.imc.tuwien.ac.at_tc-5Fblaha-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D-2D&d=DwICAg&c=yHlS04HhBraes5BQ9ueu5zKhE7rtNXt_d012z2PA6ws&r=U_T4PL6jwANfAy4rnxTj8IUxm818jnvqKFdqWLwmqg0&m=HGBSlLfU5SbOh_JfodIoRVa6I69Rsj216R2i2idPWPA&s=GxPbnc8632eZdJgUG2LT9xuLo25j8wmiwf7mi35vykc&e=>
_______________________________________________
Wien mailing list
Wien@zeus.theochem.tuwien.ac.at
<mailto:Wien@zeus.theochem.tuwien.ac.at>
https://urldefense.proofpoint.com/v2/url?u=http-3A__zeus.theochem.tuwien.ac.at_mailman_listinfo_wien&d=DwICAg&c=yHlS04HhBraes5BQ9ueu5zKhE7rtNXt_d012z2PA6ws&r=U_T4PL6jwANfAy4rnxTj8IUxm818jnvqKFdqWLwmqg0&m=HGBSlLfU5SbOh_JfodIoRVa6I69Rsj216R2i2idPWPA&s=ax2aySwdZVqULGgL-LOIT7EHit4gKJxeBu2ErcMmvEY&e=
<https://urldefense.proofpoint.com/v2/url?u=http-3A__zeus.theochem.tuwien.ac.at_mailman_listinfo_wien&d=DwICAg&c=yHlS04HhBraes5BQ9ueu5zKhE7rtNXt_d012z2PA6ws&r=U_T4PL6jwANfAy4rnxTj8IUxm818jnvqKFdqWLwmqg0&m=HGBSlLfU5SbOh_JfodIoRVa6I69Rsj216R2i2idPWPA&s=ax2aySwdZVqULGgL-LOIT7EHit4gKJxeBu2ErcMmvEY&e=>
SEARCH the MAILING-LIST at:
https://urldefense.proofpoint.com/v2/url?u=http-3A__www.mail-2Darchive.com_wien-40zeus.theochem.tuwien.ac.at_index.html&d=DwICAg&c=yHlS04HhBraes5BQ9ueu5zKhE7rtNXt_d012z2PA6ws&r=U_T4PL6jwANfAy4rnxTj8IUxm818jnvqKFdqWLwmqg0&m=HGBSlLfU5SbOh_JfodIoRVa6I69Rsj216R2i2idPWPA&s=ke6SIVUCmWlbQaSt9_oxTYR55RBkTN_pIRsUznD79B8&e=
<https://urldefense.proofpoint.com/v2/url?u=http-3A__www.mail-2Darchive.com_wien-40zeus.theochem.tuwien.ac.at_index.html&d=DwICAg&c=yHlS04HhBraes5BQ9ueu5zKhE7rtNXt_d012z2PA6ws&r=U_T4PL6jwANfAy4rnxTj8IUxm818jnvqKFdqWLwmqg0&m=HGBSlLfU5SbOh_JfodIoRVa6I69Rsj216R2i2idPWPA&s=ke6SIVUCmWlbQaSt9_oxTYR55RBkTN_pIRsUznD79B8&e=>
--
Professor Laurence Marks
"Research is to see what everybody else has seen, and to think what
nobody else has thought", Albert Szent-Gyorgi
www.numis.northwestern.edu <http://www.numis.northwestern.edu> ;
Corrosion in 4D: MURI4D.numis.northwestern.edu
<http://MURI4D.numis.northwestern.edu>
Partner of the CFW 100% program for gender equity,
www.cfw.org/100-percent <http://www.cfw.org/100-percent>
Co-Editor, Acta Cryst A
_______________________________________________
Wien mailing list
Wien@zeus.theochem.tuwien.ac.at
http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
SEARCH the MAILING-LIST at:
http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html
