Dear friend,<br><br>I found there is few supporting materials decribing what the exact meaning for mixing_beta. do you think the following paragraph from the manual of Materials Studio is suitable for this parameters?<br><br>
------------------------------------------------<br><title>SCF tab</title><link href="ms-its:Common.chm::Html%5CStylesheet.css" rel="StyleSheet"><p><span class="ftTitle">Electronic minimizer: </span>Specify the electronic
minimization method to be used for the SCF calculation. Two options are
available, <span class="value">Density Mixing</span> and <span class="value">All
Bands/EDFT</span>.</p>
<p class="tip"><span class="fttitle">Tip. </span>The <span class="value">Density
Mixing </span>option is recommended, particularly for variable occupancy
calculations. The <span class="value">All Bands/EDFT</span> method is usually
slower and requires more memory. However, the EDFT scheme is recommended for
metallic systems where converging electronic structure using <span class="value">Density Mixing</span> option proves problematic.</p>
<p><span class="ftTitle">Charge: </span>Specify the amplitude for charge density
mixing (i.e., the amplitude of the output charge density to mix with the input
charge density to obtain input for the next iteration). </p>
<p class="note"><span class="ftTitle">Note. </span>This option is enabled only if
the <span class="value">Density Mixing </span>minimization method is selected.
</p>
<p><span class="ftTitle">Spin: </span>Specify the amplitude for spin density
mixing, i.e. the amplitude of the output spin density to mix with the input spin
density to obtain input for the next iteration. </p>
<p class="note"><span class="ftTitle">Note. </span>This option in enabled only for
spin-polarized calculations using the <span class="value">Density Mixing</span>
minimization method. <br></p><p class="note">-------------------------------------------------</p><p class="note">Shoul I consider the mixing_mode option in PWSCF is equal to <span class="value">Density
Mixing </span>option in MS, and value of mixing_bate in PWSCF is equal to the one of <span class="ftTitle">Charge in MS</span>? <br></p><p class="note">Do you think I should swich on the boardening by 'occupations', 'degauss' and 'smearing' command in PWSCF?</p>
<p class="note">I also found no detail description for this three options.</p><p class="note">do you think the following text suitable for the three command in PWSCF?</p><p class="note">-----------------------------</p><p class="note">
<title>SCF tab</title><link href="ms-its:Common.chm::Html%5CStylesheet.css" rel="StyleSheet"></p><p><span class="ftTitle">Smearing: </span>Specify the broadening to be applied to
the electronic occupation. </p>
<p class="note"><span class="ftTitle">Note. </span>This option is enabled only for
variable occupancy calculations. <br></p><p class="note">-----------------------------</p><p class="note">If the answer is no, could you please give me some suggestion to understanding the command and make a better use of it.</p>
<p class="note">thank you so much for reading</p><p class="note"><br>best wishes,</p><p class="note">vega<br></p><p class="note"><br></p><p class="note"><br></p><p></p><div class="gmail_quote">On Sun, Mar 1, 2009 at 7:44 PM, vega lew <span dir="ltr"><<a href="mailto:quantumdft@gmail.com">quantumdft@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">Dear APSI<br><br>thank you for you suggestions to me.<br><br>I will try it ASAP.<br><br>vega<br>
<br><div class="gmail_quote"><div><div></div><div class="Wj3C7c">On Sun, Mar 1, 2009 at 5:08 PM, Ari Paavo Seitsonen <span dir="ltr"><<a href="mailto:ari.p.seitsonen@iki.fi" target="_blank">ari.p.seitsonen@iki.fi</a>></span> wrote:<br>
</div></div><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"><div><div></div><div class="Wj3C7c"><br>
Dear Vega,<br>
<br>
Just my guesses and suggestions: One could try mixing of the density, like<br>
<br>
&electrons<br>
mixing_beta = 0.7<br>
/<br>
<br>
(or a value even smaller than 0.7, or some other parametres for the mixing) since with a defect you might now have defect levels in the band gap, leading to a more difficult a convergence. Eventually one could also switch on the broadening of the occupation numbers, eventually switching it off for the physical/production jobs, but just to check if the problem in convergence comes due to this.<br>
<br>
And in the original paper the authors discuss spin-polarisation, one might test also this (nspin = 2), with different initial magnetisations [starting_magnetization(xx) = ...] for the atoms surrounding the defect.<br>
<br>
Greetings,<br>
<br>
apsi<div><br>
<br>
<br>
On Sun, 1 Mar 2009, vega lew wrote:<br>
<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
Dear all,<br>
<br>
I am planning to calculate the Oxygen vacancy properties of TiO2 surfaces.<br>
The calculation for the ideal surfaces are quite normal and the results are<br>
in line with the one that literature reported. But, when I tried to<br>
calculate the anatase 101 surface with an Oxygen vacancy (O2c was removed<br>
directly from the stoichiometric Anatase 101as described in J. Phys. Chem. C<br>
2007, 111, 16397-16404, I encounter the problem of convergence for SCF<br>
cycle. I tried to add 20% more empty band to the system the problem still<br>
laid in. How could I overcome the problem?<br>
<br>
my input file was attached at the bottom of the mail<br>
<br>
thank you for reading. Any hints will be appreciated.<br>
<br>
vega<br>
<br>
</blockquote>
<br></div>
...<div><div></div><div><br>
<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<br>
&SYSTEM<br>
ibrav = 8,<br>
celldm(1) =19.3269,<br>
celldm(2) = 1.1094,<br>
celldm(3) = 1.7450,<br>
nat = 71,<br>
ntyp = 2,<br>
nosym = .true.,<br>
ecutwfc = 30,<br>
ecutrho = 300,<br>
/<br>
<br>
&ELECTRONS<br>
<br>
/<br>
<br>
&IONS<br>
ion_dynamics = 'bfgs',<br>
/<br>
<br>
</blockquote>
<br></div></div><font color="#888888">
-- <br>
-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-<br>
Ari P Seitsonen / <a href="mailto:Ari.P.Seitsonen@iki.fi" target="_blank">Ari.P.Seitsonen@iki.fi</a> / <a href="http://www.iki.fi/%7Eapsi/" target="_blank">http://www.iki.fi/~apsi/</a><br>
IMPMC, CNRS & Université Pierre et Marie Curie<br>
Tel: +33-1-4427 7542, Fax: +33-1-4427 3785, GSM: +33-6-6736 3820</font><br></div></div>_______________________________________________<br>
Pw_forum mailing list<br>
<a href="mailto:Pw_forum@pwscf.org" target="_blank">Pw_forum@pwscf.org</a><br>
<a href="http://www.democritos.it/mailman/listinfo/pw_forum" target="_blank">http://www.democritos.it/mailman/listinfo/pw_forum</a><br>
<br></blockquote></div><div><div></div><div class="Wj3C7c"><br><br clear="all"><br>-- <br>==================================================================================<br>Vega Lew ( weijia liu)<br>PH.D Candidate in Chemical Engineering<br>
State Key Laboratory of Materials-oriented Chemical Engineering<br>
College of Chemistry and Chemical Engineering<br>Nanjing University of Technology, 210009, Nanjing, Jiangsu, China<br>******************************************************************************************************************<br>
Email: <a href="mailto:vegalew@gmail.com" target="_blank">vegalew@gmail.com</a><br>Office: Room A705, Technical Innovation Building, Xinmofan Road 5#, Nanjing, Jiangsu, China <br>****************************************************************************************************************** <br>
</div></div></blockquote></div><br><br clear="all"><br>-- <br>==================================================================================<br>Vega Lew ( weijia liu)<br>PH.D Candidate in Chemical Engineering<br>State Key Laboratory of Materials-oriented Chemical Engineering<br>
College of Chemistry and Chemical Engineering<br>Nanjing University of Technology, 210009, Nanjing, Jiangsu, China<br>******************************************************************************************************************<br>
Email: <a href="mailto:vegalew@gmail.com">vegalew@gmail.com</a><br>Office: Room A705, Technical Innovation Building, Xinmofan Road 5#, Nanjing, Jiangsu, China <br>****************************************************************************************************************** <br>